Integrated touch panel for a tft display

ABSTRACT

This relates to displays for which the use of dual function capacitive elements does not result in any decreases of the aperture of the display. Thus, touch sensitive displays that have aperture ratios that are no worse than similar non-touch sensing displays can be manufactured. More specifically, this relates to placing touch sensing opaque elements so as to ensure that they are substantially overlapped by display related opaque elements, thus ensuring that the addition of the touch sensing elements does not substantially reduce the aperture ratio. The touch sensing display elements can be, for example, common lines that connect various capacitive elements that are configured to operate collectively as an element of the touch sensing system.

FIELD OF THE INVENTION

This relates generally to multi-touch sensing displays, and morespecifically to combining multi-touch sensing functionality and LCDdisplay functionality.

BACKGROUND OF THE INVENTION

Many types of input devices are presently available for performingoperations in a computing system, such as buttons or keys, mice,trackballs, joysticks, touch sensor panels, touch screens and the like.Touch screens, in particular, are becoming increasingly popular becauseof their ease and versatility of operation as well as their decliningprice. Touch screens can include a touch sensor panel, which can be aclear panel with a touch-sensitive surface, and a display device such asa liquid crystal display (LCD) that can be positioned partially or fullybehind the panel so that the touch-sensitive surface can cover at leasta portion of the viewable area of the display device. Touch screens canallow a user to perform various functions by touching the touch sensorpanel using a finger, stylus or other object at a location dictated by auser interface (UI) being displayed by the display device. In general,touch screens can recognize a touch event and the position of the touchevent on the touch sensor panel, and the computing system can theninterpret the touch event in accordance with the display appearing atthe time of the touch event, and thereafter can perform one or moreactions based on the touch event.

Multi-touch screens or multi-touch panels are a further development oftouch screens. These allow for the device to sense multiple touch eventsat a time. More specifically, a multi-touch panel can allow a device tosense the outlines of all fingers or other objects that are touching thepanel at a given time. Thus, while a single touch panel may only sense asingle location that is being touched, a multi-touch panel can providedan entire “touch graphic” which indicates the status (touched or nottouched) of a plurality of touch pixels at the panel.

An exemplary multi-touch enabled display is disclosed by U.S. patentapplication Ser. No. 11/649,998 filed on Jan. 3, 2007, entitled“PROXIMITY AND MULTI-TOUCH SENSOR DETECTION AND DEMODULATION”, Pub. No.2008/0158172 which is hereby incorporated by reference herein in itsentirety for all purposes. Early multi-touch displays requiredmanufacturing of a multi-touch sensing panel and a separate displaypanel. The two panels can later be laminated together to form amulti-touch display. Later generations of the technology provided forcombining the display and multi-touch functionality in order to reducepower consumption, make the multi-touch display thinner, reduce costs ofmanufacturing, improve brightness, etc. Examples of such integratedmulti-touch displays are disclosed by U.S. application Ser. No.11/818,422 filed on June 13, 2007 and entitled “INTEGRATED IN-PLANESWITCHING”, and U.S. application Ser. No. 12/240,964, filed on Jul. 3,2008 and entitled “DISPLAY WITH DUAL-FUNCTION CAPACITIVE ELEMENTS,” bothof which are incorporate by reference herein in their entireties for allpurposes.

However, some of the schemes for integration can require placing someadditional non-transparent elements in the thin film transistor (TFT)layer of the display. Such additional non-transparent elements canreduce the aperture of the display (the aperture being the portion ofthe display that actually transmits light). Reduction of the aperturecan cause reduction of the brightness of the display as well as areduction in the viewable angle of the display.

SUMMARY OF THE INVENTION

This relates to displays including pixels with dual-function capacitiveelements. Specifically, these dual-function capacitive elements formpart of the display system that generates an image on the display, andalso form part of a touch sensing system that senses touch events on ornear the display. The capacitive elements can be, for example,capacitors in pixels of an LCD display that are configured to operateindividually, each as a pixel storage capacitor, or electrode, of apixel in the display system, and are also configured to operatecollectively as elements of the touch sensing system. In this way, forexample, a display with integrated touch sensing capability may bemanufactured using fewer parts and/or processing steps, and the displayitself may be thinner and brighter.

Furthermore, this relates to displays for which the use of dual functioncapacitive elements does not result in any decreases of the aperture ofthe display. Thus, touch sensitive displays that have aperture ratiosthat are no worse than similar non-touch sensing displays can bemanufactured. More specifically, this relates to placing touch sensingopaque elements so as to ensure that they are substantially overlappedby display related opaque elements, thus ensuring that the addition ofthe touch sensing elements does not substantially reduce the apertureratio. The touch sensing display elements can be, for example, commonlines that connect various capacitive elements that are configured tooperate collectively as an element of the touch sensing system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a partial circuit diagram of an example LCD displayincluding a plurality of LCD pixels according to embodiments of thepresent invention.

FIGS. 2A and 2B illustrate example regions formed by breaks in verticaland horizontal common voltage lines according to embodiments of theinvention.

FIG. 3 illustrates partial circuit diagrams of a pixel 301 of a driveregion and a pixel 303 of an example sense region.

FIG. 4A illustrates example signals applied to the pixels of a driveregion during an LCD phase and during a touch phase according toembodiments of the invention.

FIG. 4B illustrates example signals applied to the pixels of a senseregion during an LCD phase and during a touch phase according toembodiments of the invention.

FIG. 5A illustrates details of an example operation of a storagecapacitor of a drive region during a touch phase according toembodiments of the invention.

FIG. 5B illustrates details of an example operation of a storagecapacitor of a sense region during a touch phase according toembodiments of the invention.

FIG. 6A illustrates a partial view of an example touch screen havingregions of pixels with dual-function capacitive elements that operate asLCD elements and as touch sensors according to embodiments of theinvention.

FIG. 6B illustrates a partial view of an example touch screen includingmetal traces running in the border areas of the touch screen accordingto embodiments of the invention.

FIG. 6C illustrates an example connection of columns and row patches tothe metal traces in the border area of the touch screen according toembodiments of the invention.

FIG. 7 illustrates a top view of an example column and adjacent rowpatches according to embodiments of the invention.

FIG. 8A is an example plot of an x-coordinate of a finger touch versusmutual capacitance seen at a touch pixel for a two adjacent touch pixelsin a single row having wide spacings according to embodiments of theinvention.

FIG. 8B is an example plot of an x-coordinate of a finger touch versusmutual capacitance seen at a touch pixel for two adjacent touch pixelsin a single row having wide spacings where spatial interpolation hasbeen provided according to embodiments of the invention.

FIG. 8C illustrates a top view of an example column and adjacent rowpatch pattern useful for larger touch pixel spacings according toembodiments of the invention.

FIG. 9A illustrates an example touch screen including sense (or drive)regions formed as columns and rows of polygonal regions (bricks)according to embodiments of the invention.

FIG. 9B illustrates a close-up view of a portion of the example touchscreen of FIG. 9A.

FIG. 9C illustrates a portion of example touch screen of FIG. 9Aincluding bricks associated with columns C0 and C1 and connecting yVcomlines connecting the bricks to bus lines according to embodiments of theinvention.

FIG. 10 illustrates a portion of example zig-zag double interpolatedtouch screen that can further reduce the stray capacitance between theconnecting yVcom lines and the sense regions according to embodiments ofthe invention.

FIG. 11 illustrates a patterning of a first metal layer (M1) of pixelsin an example electrically controlled birefringence (ECB) LCD displayusing amorphous silicon (a-Si) according to embodiments of theinvention.

FIG. 12 illustrates a patterning step in which island patterns of a-Siare formed in the example ECB LCD display using a-Si according toembodiments of the invention.

FIG. 13 illustrates connections formed in a pixel in the example ECB LCDdisplay using a-Si according to embodiments of the invention.

FIG. 14 illustrates patterning of a second metal layer (M2) of pixels inthe example ECB LCD display using a-Si according to embodiments of theinvention.

FIG. 15 illustrates planarization (PLN) contact layers in the exampleECB LCD display using a-Si according to embodiments of the invention.

FIG. 16 illustrates reflector (REF) layers in the example ECB LCDdisplay using a-Si according to embodiments of the invention.

FIG. 17 illustrates passivation (PASS) contacts in the example ECB LCDdisplay using a-Si according to embodiments of the invention.

FIG. 18 illustrates semi-transparent conductive material (such as ITO1))layers that form pixel electrodes in the example ECB LCD display usinga-Si according to embodiments of the invention.

FIG. 19 illustrates a plan view of completed pixels in the example ECBLCD display using a-Si according to embodiments of the invention.

FIGS. 20A-D illustrate side views of completed pixels in the example ECBLCD display using a-Si according to embodiments of the invention.

FIGS. 21 and 22 illustrate a comparative analysis of the storagecapacitances of pixels in the example ECB LCD display using a-Siaccording to embodiments of the invention.

FIG. 23 illustrates aperture ratio estimations for pixels in the exampleECB LCD display using a-Si according to embodiments of the invention.

FIG. 24 illustrates an example modification in the example ECB LCDdisplay using a-Si according to embodiments of the invention.

FIG. 25 illustrates the patterning of a layer of poly-Si of pixels in anexample in-plane switching (IPS) LCD display using low temperaturepolycrystalline silicon (LTPS) according to embodiments of theinvention.

FIG. 26 illustrates the patterning of a first metal layer (M1) of pixelsin the example IPS LCD display using LTPS according to embodiments ofthe invention.

FIG. 27 illustrates vias formed in pixels in the example IPS LCD displayusing LTPS according to embodiments of the invention.

FIG. 28 illustrates the patterning of a second metal layer (M2) ofpixels in the example IPS LCD display using LTPS according toembodiments of the invention.

FIG. 29 illustrates a first layer of transparent conductive material,such as ITO, formed on pixels in the example IPS LCD display using LTPSaccording to embodiments of the invention.

FIG. 30 illustrates a connection in the example IPS LCD display usingLTPS according to embodiments of the invention.

FIG. 31 illustrates a second layer of transparent conductor, such asITO, formed on pixel in the example IPS LCD display using LTPS accordingto embodiments of the invention.

FIG. 32 illustrates a plan view of completed pixels in the example IPSLCD display using LTPS according to embodiments of the invention.

FIG. 33 illustrates a side view of a pixel in the example IPS LCDdisplay using LTPS according to embodiments of the invention.

FIG. 34 illustrates the storage capacitances of two pixels in theexample IPS LCD display using LTPS according to embodiments of theinvention.

FIG. 35 illustrates the patterning of a layer of poly-Si of pixels in anexample IPS LCD display using LTPS in which a yVcom line is formed in anM2 layer according to embodiments of the invention.

FIG. 36 illustrates the patterning of a first metal layer (M1) of pixelsin the example IPS LCD display using LTPS in which a yVcom line isformed in an M2 layer according to embodiments of the invention.

FIG. 37 illustrates vias formed in pixels in the example IPS LCD displayusing LTPS in which a yVcom line is formed in an M2 layer according toembodiments of the invention.

FIG. 38 illustrates patterning of a second metal layer (M2) of pixels inthe example IPS LCD display using LTPS in which a yVcom line is formedin an M2 layer according to embodiments of the invention.

FIG. 39 illustrates a first layer of transparent conductive material,such as ITO, formed on pixels in the example IPS LCD display using LTPSin which a yVcom line is formed in an M2 layer according to embodimentsof the invention.

FIG. 40 illustrates connections in the example IPS LCD display usingLTPS in which a yVcom line is formed in an M2 layer according toembodiments of the invention.

FIG. 41 illustrates a second layer of transparent conductor, such asITO, formed on pixels in the example IPS LCD display using LTPS in whicha yVcom line is formed in an M2 layer according to embodiments of theinvention.

FIG. 42 illustrates a plan view of completed pixels in the example IPSLCD display using LTPS in which a yVcom line is formed in an M2 layeraccording to embodiments of the invention.

FIG. 43 illustrates a side view of a pixel in the example IPS LCDdisplay using LTPS in which a yVcom line is formed in an M2 layeraccording to embodiments of the invention.

FIG. 44 illustrates a semiconductor layer of poly-Si in an example ECBLCD display using LTPS according to embodiments of the invention.

FIG. 45 illustrates a first layer of metal (M1) in the example ECB LCDdisplay using LTPS according to embodiments of the invention.

FIG. 46 illustrates connections in the example ECB LCD display usingLTPS according to embodiments of the invention.

FIG. 47 illustrates a second metal layer (M2) in the example ECB LCDdisplay using LTPS according to embodiments of the invention.

FIG. 48 illustrates a connection layer in the example ECB LCD displayusing LTPS according to embodiments of the invention.

FIG. 49 illustrates a reflector layer in the example ECB LCD displayusing LTPS according to embodiments of the invention.

FIG. 50 illustrates an ITO layer in the example ECB LCD display usingLTPS according to embodiments of the invention.

FIG. 51 illustrates a completed pixel in the example ECB LCD displayusing LTPS according to embodiments of the invention.

FIG. 52 illustrates a side view of a pixel in the example ECB LCDdisplay using LTPS according to embodiments of the invention.

FIG. 53 illustrates a calculation of the storage capacitance of a pixelin the example ECB LCD display using LTPS according to embodiments ofthe invention.

FIG. 54 illustrates an aperture ratio estimation of pixels in theexample ECB LCD display using LTPS according to embodiments of theinvention.

FIG. 55 illustrates an example modification in the example ECB LCDdisplay using LTPS according to embodiments of the invention.

FIG. 56 illustrates a portion of a touch screen that includes an examplegrounded separator region according to embodiments of the invention.

FIG. 57 is a side view of the example touch screen of FIG. 56, whichillustrates an example high R shield according to embodiments of theinvention.

FIG. 58 illustrates a side view of a portion of an example touch screenincluding black mask lines of a black mask and metal lines under theblack mask lines according to embodiments of the invention.

FIG. 59 illustrates an example black mask layout according toembodiments of the invention.

FIG. 60 illustrates an exemplary layout of conductive lines in a touchsensing display according to embodiments of the invention.

FIGS. 61A and B illustrate two exemplary FFS TFT LCD configurations.

FIGS. 62A-D illustrate several exemplary ways to connect common lines toa common electrode according to embodiments of the invention.

FIG. 63 illustrates an exemplary common electrode on bottom FFS TFT LCDaccording to embodiments of the invention.

FIG. 64 illustrates another view of an exemplary common electrode onbottom FFS TFT LCD according to embodiments of the invention.

FIG. 65 illustrates an exemplary common electrode on top FFS TFT LCDaccording to embodiments of the invention.

FIG. 66 illustrates another view of an exemplary common electrode on topFFS TFT LCD according to embodiments of the invention.

FIG. 67 illustrates an example IPS-based touch-sensing display in whichthe pixel regions serve multiple functions.

FIG. 68 illustrates an example computing system that can include one ormore of the example embodiments of the invention.

FIG. 69A illustrates an example mobile telephone that can include atouch screen including pixels with dual-function capacitive elementsaccording to embodiments of the invention.

FIG. 69B illustrates an example digital media player that can include atouch screen including pixels with dual-function capacitive elementsaccording to embodiments of the invention.

FIG. 69C illustrates an example personal computer that can include atouch screen including pixels with dual-function capacitive elementsaccording to embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description of preferred embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments in which theinvention can be practiced. It is to be understood that otherembodiments can be used and structural changes can be made withoutdeparting from the scope of the embodiments of this invention.

This relates to displays including pixels with dual-function capacitiveelements. Specifically, these dual-function capacitive elements formpart of the display system that generates an image on the display, andalso form part of a touch sensing system that senses touch events on ornear the display. The capacitive elements can be, for example,capacitors in pixels of an LCD display that are configured to operateindividually, each as a pixel storage capacitor, or electrode, of apixel in the display system, and are also configured to operatecollectively as elements of the touch sensing system. In this way, forexample, a display with integrated touch sensing capability may bemanufactured using fewer parts and/or processing steps, and the displayitself may be thinner and brighter.

Furthermore, this relates to dual function displays as discussed above,that further feature additional improvements of the aperture (and thusthe brightness and the viewing angle) of the display. Said additionalimprovements can be realized by ensuring that touch sensing relatedcommon lines are positioned in such a manner that they do notsignificantly degrade the aperture ratio of the display from what itwould have been had no touch sensing elements been present. For example,the touch sensing related common lines can be positioned in such amanner so that they are overlapped by various opaque display relatedelements.

While the present invention is described in relation to specific typesof displays and specific schemes of capacitance based touch sensing, itis not so limited. A person of skill in the art would recognize thatembodiments of the invention can be used in conjunction with other typesof displays and touch sensing schemes, as long as the displays includepixels having capacitance causing electrodes, and the touch sensingschemes at least partially rely on sensing capacitance.

FIG. 1 is a partial circuit diagram of an example LCD display 100including a plurality of LCD pixels according to embodiments of thepresent invention. The pixels of panel 100 are configured such that theyare capable of dual-functionality as both LCD pixels and touch sensorelements. That is, the pixels include capacitive elements or electrodes,that can operate as part of the LCD display circuitry of the pixels andthat can also operate as elements of touch sensing circuitry. In thisway, panel 100 can operate as an LCD display with integrated touchsensing capability. FIG. 1 shows details of pixels 101, 102, 103, and104 of display 100.

Pixel 102 includes a thin film transistor (TFT) 155 with a gate 155 a, asource 155 b, and a drain 155 c. Pixel 102 also includes a storagecapacitor, Cst 157, with an upper electrode 157 a and a lower electrode157 b, a liquid crystal capacitor, Clc 159, with a pixel electrode 159 aand a common electrode 159 b, and a color filter voltage source, Vcf161. If a pixel is an in-plane-switching (IPS) pixel, Vcf can be, forexample, a fringe field electrode connected to a common voltage line inparallel with Cst 157. If a pixel does not utilize IPS, Vcf 151 can be,for example, an ITO layer on the color filter glass. Pixel 102 alsoincludes a portion 117 a of a data line for green (G) color data, Gdataline 117, and a portion 113 b of a gate line 113. Gate 155 a isconnected to gate line portion 113 b, and source 155 b is connected toGdata line portion 117 a. Upper electrode 157 a of Cst 157 is connectedto drain 155 c of TFT 155, and lower electrode 157 b of Cst 157 isconnected to a portion 121 b of a common voltage line that runs in thex-direction, xVcom 121. Pixel electrode 159 a of Clc 159 is connected todrain 155 c of TFT 155, and common electrode 159 b of Clc 159 isconnected to Vcf 151.

The circuit diagram of pixel 103 is identical to that of pixel 102.However, color data line 119 running through pixel 103 carries blue (B)color data. Pixels 102 and 103 can be, for example, conventional LCDpixels.

Similar to pixels 102 and 103, pixel 101 includes a thin film transistor(TFT) 105 with a gate 105 a, a source 105 b, and a drain 105 c. Pixel101 also includes a storage capacitor, Cst 107, with an upper electrode107 a and a lower electrode 107 b, a liquid crystal capacitor, Clc 109,with a pixel electrode 109 a and a common electrode 109 b, and a colorfilter voltage source, Vcf 111. Pixel 101 also includes a portion 115 aof a data line for red (R) color data, Rdata line 115, and a portion 113a of gate line 113. Gate 105 a is connected to gate line portion 113 a,and source 105 b is connected to Rdata line portion 115 a. Upperelectrode 107 a of Cst 107 is connected to drain 105 c of TFT 105, andlower electrode 107 b of Cst 107 is connected to a portion 121 a ofxVcom 121. Pixel electrode 109 a of Clc 109 is connected to drain 105 cof TFT 105, and common electrode 109 b of Clc 109 is connected to Vcf111.

Unlike pixels 102 and 103, pixel 101 also includes a portion 123 a of acommon voltage line running in the y-direction, yVcom 123. In addition,pixel 101 includes a connection 127 that connects portion 121 a toportion 123 a. Thus, connection 127 connects xVcom 121 and yVcom 123.

Pixel 104 is similar to pixel 101, except that a portion 125 a of ayVcom 125 has a break (open) 131, and a portion 121 b of xVcom 121 has abreak 133.

As can be seen in FIG. 1, the lower electrodes of storage capacitors ofpixels 101, 102, and 103 are connected together by xVcom 121. This is aconventional type of connection in many LCD panels and, when used inconjunction with conventional gate lines, data lines, and transistors,allows pixels to be addressed. The addition of vertical common voltagelines along with connections to the horizontal common voltage linesallows grouping of pixels in both the x-direction and y-direction, asdescribed in further detail below. For example, yVcom 123 and connection127 to xVcom 121 can allow the storage capacitors of pixels 101, 102,and 103 to be connected to storage capacitors of pixels that are aboveand below pixels 101, 102, 103 (the pixels above and below are notshown). For example, the pixels immediately above pixels 101, 102, and103 can have the same configurations as pixels 101, 102, and 103,respectively. In this case, the storage capacitors of the pixelsimmediately above pixels 101, 102, and 103 would be connected to thestorage capacitors of pixels 101, 102, and 103.

In general, an LCD panel could be configured such that the storagecapacitors of all pixels in the panel are connected together, forexample, through at least one vertical common voltage line withconnections to a plurality of horizontal common voltage lines. AnotherLCD panel could be configured such that different groups of pixels areconnected together to form a plurality of separate regions ofconnected-together storage capacitors.

One way to create separate regions is by forming breaks (opens) in thehorizontal and/or vertical common lines. For example, yVcom 125 of panel100 has a break 131, which can allow pixels above the break to beisolated from pixels below the break. Likewise, xVcom 121 has a break133, which can allow pixels to the right of the break to be isolatedfrom pixels to the left of the break.

FIGS. 2A and 2B illustrate example regions formed by breaks in verticaland horizontal common voltage lines according to embodiments of theinvention. FIG. 2A shows a TFT glass region layout. FIG. 2A shows aregion 201, a region 205, and a region 207. Each region 201, 205, and207 is formed by linking storage capacitors of a plurality of pixels(not shown in detail) through common voltage lines in the verticaldirection (y-direction) and in the horizontal direction (x-direction).For example, the enlarged area of FIG. 2A shows pixel blocks 203 a-e. Apixel block includes one or more pixels, in which at least one of thepixels includes a vertical common line, yVcom. FIG. 1, for example,illustrates a pixel block that includes pixels 101-103, in which pixel101 includes yVcom 123. As seen in FIG. 2A, pixel block 203 a isconnected in the horizontal direction to pixel block 203 b through ahorizontal common line, xVcom 206 Likewise, pixel block 203 a isconnected in the vertical direction to pixel block 203 c through avertical common line, yVcom 204. A break in xVcom 206 prevents block 203a from being connected to block 203 d, and a break in yVcom 204 preventsblock 203 a from being connected to block 203 e. Regions 201 and 207form a capacitive element that can provide touch sensing informationwhen connected to suitable touch circuitry, such as touch circuitry 213of touch ASIC 215. The connection is established by connecting theregions to switch circuitry 217, which is described in more detailbelow. (Note, for IPS-type displays there are no conductive dotsrequired. In this case, the xVcom and yVcom regions may simply extendedwith metal traces that go to the Touch ASIC which is bonded to the glassin a similar way as the LCD driver chip (through anisotropic conductiveadhesive). However, for non-IPS-type displays, the conductive dots maybe needed to bring the VCOM regions on the color filter plate intocontact with the corresponding regions on the TFT plate.) Likewise,region 201 and region 205 form a capacitive element that can providetouch information when connected to touch circuitry 213. Thus, region201 serves as a common electrode to regions 205 and 207, which arecalled, for example, sense electrodes. The foregoing describes mutualcapacitance mode of touch sensing. It is also possible to use eachregion independently to measure self-capacitance.

Some embodiments of the invention are directed to fringe field switchingTFT liquid crystal displays (FFS TFT LCDs), which are considered to a bespecific type of in plane switching (IPS) displays. An example of an FFSTFT LCD is described by Lee, Seung Hee et al., “Ultra-FFS TFT-LCD withSuper Image Quality, Fast Response Time, and Strong Pressure-ResistantCharacteristics,” Journal of the Society for Information displays Oct.2, 2002. The above publication is hereby incorporated by referenceherein in its entirety for all purposes. Fringe field switching displaysprovide for a common electrode, which is an electrode that forms oneplate of the storage capacitor for each pixel but is common for a numberof pixels. In some displays the common electrode can be common for theentire display; in others, multiple common electrodes can be used forrows of pixels or the like.

In FFS TFT LCD embodiments of the present invention, the commonelectrodes can be cut or shaped along the touch regions. Thus, forexample, touch regions 201, 205 and 207 may comprise different commonelectrodes that are separated from their neighboring common electrodesby empty space or by an insulator. Thus each common electrode may be anindividual touch region. Since the common electrodes are conducting,VCOM lines are technically not required for the FFS TFT LCD embodiments.However, the common electrodes can be made out of transparent conductivematerial (such as ITO) as usually required for FFS TFT LCDs. Transparentconductors usually have relatively high resistances. This can reduce thesensitivity of touch regions 201, 205 and 207, especially at highfrequencies. Therefore, some embodiments provide that even if a FFS TFTdisplay is used, non transparent, low resistance common lines can beused to reduce the effective resistance of the touch regions. However,in these cases, the common lines can vary in density as needed and neednot go through every pixel.

As described above, the regions connected-together storage capacitors ofpixels can be formed using vias between common voltage lines, such asxVcom and yVcom in FIG. 1, and using selective breaks in the commonvoltage lines. Thus, FIG. 2A illustrates one way in which vias or otherconnections and selective breaks can be used to create capacitiveregions that can span many pixels. Of course, in light of the presentdisclosure, one skilled in the art would readily understand that regionsof other shapes and configurations can be created.

FIG. 2B shows a CF glass patterned ITO region layout, which may or maynot be needed, depending on the type of LCD technology used by thepixel. For example, such CF ITO regions would not be needed in the casethat the LCD pixel utilizes in-plane-switching (IPS). However, FIG. 2Bis directed to non-IPS LCD displays in which a voltage is applied toliquid crystal between an upper and lower electrode. FIG. 2B shows upperregions 221, 223, and 225, which correspond to lower (in non-IPSdisplays) regions 201, 205, and 207, respectively, of FIG. 2A. FIG. 2Bshows conductive dots 250 contacting regions 251, 255, and 257.Conductive dots 250 connect the corresponding upper and lower regionssuch that when to the upper electrodes of pixels in an upper region aredriven, the corresponding lower electrodes of pixels in the lower regionare also driven. As a result, the relative voltage between the upper andlower electrodes remains constant, even while the pixels are beingdriven by, for example, a modulated signal. Thus the voltage applied tothe liquid crystal can remain constant during a touch phase, forexample. In particular, the constant relative voltage can be the pixelvoltage for operation of the LCD pixel. Therefore, the pixels cancontinue to operate (i.e., display an image) while touch input is beingdetected.

A touch sensing operation according to embodiments of the invention willbe described with reference to FIGS. 3-5B. For the sake of clarity, theoperation is described in terms of a single drive pixel and a singlesense pixel. However, it is understood that the drive pixel is connectedto other drive pixels in a drive region and the sense pixel is connectedto other sense pixels in the sense region, as described above. Thus, inactual operation, the entire drive region is driven, and the entiresense region can contribute to the sensing of touch.

FIG. 3 shows partial circuit diagrams of a pixel 301 of a drive regionand a pixel 303 of an example sense region. Pixels 301 and 303 includeTFTs 307 and 309, gate lines 311 and 312, data lines 313 and 314, xVcomlines 315 and 316, fringe field electrodes 319 and 321, and storagecapacitors 323 and 325. Storage capacitors 323 and 325 each have acapacitance of about 300 fF (femto-Farads). A lower electrode of fringefield electrode 321 of pixel 303 can be connected, through xVcom 316, toa charge amplifier 326 in the sense circuitry. Charge amplifier 326holds this line at a virtual ground such that any charge that getsinjected from fringe field electrode 321 shows up as a voltage output ofthe amplifier. While the feedback element of the amplifier is shown as acapacitor, it may also function as a resistor or a combination of aresistor and capacitor. The feedback can also be, for example, aresistor and capacitor feedback for minimizing die-size of the touchsensing circuitry. FIG. 3 also shows a finger 327 that creates a straycapacitance of approximately 3 fF with a cover glass (not shown), andshows other stray capacitances in the pixels, each of which isapproximately 3 fF.

FIG. 4A shows example signals applied through xVcom 315 to the pixels ofthe drive region, including pixel 301, during an LCD phase and during atouch phase. During the LCD phase, xVcom 315 is driven with a squarewave signal of 2.5V+/−2.5V, in order to perform LCD inversion. The LCDphase is 12 ms in duration. In the touch phase, xVcom 315 is driven with15 to 20 consecutive stimulation phases lasting 200 microseconds each.The stimulation signals in this case are sinusoidal signals of 2.5V+/−2Veach having the same frequency and a relative phase of either 0 degreesor 180 degrees (corresponding to “+” and “−” in FIG. 4A). The touchphase is 4 ms in duration.

FIG. 5A shows details of the operation of storage capacitor 323 duringthe touch phase. In particular, because the capacitance of storagecapacitor 323 is much higher than the other capacitances, i.e., straycapacitances shown in FIG. 3, almost all (approximately 90%) of the ACcomponent of the 2.5V+/−2V sinusoidal stimulation signal that is appliedat the lower electrode of the storage capacitor is transferred to theupper electrode. Therefore, the upper electrode, which is charged to 4.5volts DC for the operation of the LCD, sees a sinusoidal signal of4.5V+/−1.9V. These signals are passed to the corresponding left andright comb structures of fringe field electrode 319. In this way, bothcomb structures of fringe field electrode 319 can be modulated with asignal having an AC component of approximately +/−2V in amplitude (+/−2Von one, +/−1.9V on the other). Thus, fringe field electrode 319,together with the other fringe field electrodes of pixels in the driveregion being similarly driven, can operate as a drive line forcapacitive sensing.

It is important to note that at the same time fringe field electrode 319is configured to operate as a drive element for the touch sensingsystem, the fringe field electrode continues to operate as a part of theLCD display system. As shown in FIG. 5A, while the voltages of the combstructures of fringe field electrode are each modulated at approximately+/−2V, the relative voltage between the comb structures remainsapproximately constant at 2V +/−0.1V. This relative voltage is thevoltage that is seen by the liquid crystal of the pixel for the LCDoperation. The 0.1V AC variance in the relative voltage during the touchphase should have an acceptably low effect on the LCD display,particularly since the AC variance would typically have a frequency thatis higher than the response time for the liquid crystal. For example,the stimulation signal frequency, and hence the frequency of the ACvariance, would typically be more than 100 kHz. However, the responsetime for liquid crystal is typically less than 100 Hz. Therefore, thefringe field electrode's function as a drive element in the touch systemshould not interfere with the fringe field electrode's LCD function.

Referring now to FIGS. 3, 4B, and 5B, an example operation of the senseregion will now be described. FIG. 4B shows signals applied throughxVcom 316 to the pixels of the sense region, including pixel 303, duringthe LCD and touch phases described above. As with the drive region,xVcom 316 is driven with a square wave signal of 2.5V +/−2.5V in orderto perform LCD inversion during the LCD phase. During the touch phase,xVcom 316 is connected to amplifier 326, which holds the voltage at ornear a virtual ground of 2.5V. Consequently, fringe field electrode 321is also held at 2.5V. As shown in FIG. 3, fringing electrical fieldspropagate from fringe field electrode 319 to fringe field electrode 321.As described above, the fringing electric fields are modulated atapproximately +/−2V by the drive region. When these fields are receivedby the top electrode of fringing field electrode 321, most of the signalgets transferred to the lower electrode, because pixel 303 has the sameor similar stray capacitances and storage capacitance as pixel 301.Because xVcom 316 is connected to charge amplifier 326, and is beingheld at virtual ground, any charge that gets injected will show up as anoutput voltage of the charge amplifier. This output voltage provides thetouch sense information for the touch sensing system. For example, whenfinger 327 gets close to the fringing fields, it captures some fieldsand grounds them, which causes a disturbance in the fields. Thisdisturbance can be detected by the touch system as a disturbance in theoutput voltage of charge amplifier 326. FIG. 5B shows that approximately90% of a received fringing field at pixel 302 which impinges onto theelectrode half of the capacitor which is also connected to the drain ofthe TFT 325 will be transferred to charge amplifier 326. 100% of thecharge that impinges onto the electrode half of the capacitor which isconnected directly to XVCOM 316 will be transferred to charge amplifier326. The ratio of charge impinging onto each electrode will depend onthe LCD design. For non-IPS, near 100% of the finger affected chargewill impinge on the VCOM electrode because the patterned CF plate isnearest the finger. For IPS type display the ratio will be closer tohalf and half because each part of the electrode has approximately equalarea (or ¼ vs. ¾) facing the finger. For some sub-types of IPS displays,the fringing electrodes are not coplanar, and the majority of the upwardfacing area is devoted to the VCOM electrode.

The example driving and sensing operations of FIGS. 3, 4A-B, and 5A-Bare described using single pixels for the sake of clarity. Some examplelayouts and operations of drive regions and sense regions according toembodiments of the invention will now be described with reference toFIGS. 6A-C, 7, 8A-C, 9A-C, and 10.

FIG. 6A illustrates a partial view of an example touch screen 600 havingregions of pixels with dual-function capacitive elements that operate asLCD elements and as touch sensors according to embodiments of theinvention. In the example of FIG. 6A, touch screen 600 having eightcolumns (labeled a through h) and six rows (labeled 1 through 6) isshown, although it should be understood that any number of columns androws can be employed. Columns a through h can be formed fromcolumn-shaped regions, although in the example of FIG. 6A, one side ofeach column includes staggered edges and notches designed to createseparate sections in each column. Each of rows 1 through 6 can be formedfrom a plurality of distinct patches or pads within the regions, eachpatch connected to a border area through one or more yVcom lines runningto the border area of touch screen 600 for enabling all patches in aparticular row to be connected together through metal traces (not shownin FIG. 6A) running in the border areas. These metal traces can berouted to a small area on one side of touch screen 600 and connected toa flex circuit 602. As shown in the example of FIG. 6A, the patchesforming the rows can be formed, by selective placement of breaks inxVcom lines and yVcom lines, for example, in a generally pyramid-shapedconfiguration. In FIG. 6A, for example, the patches for rows 1-3 betweencolumns a and b are arranged in an inverted pyramid configuration, whilethe patches for rows 4-6 between columns a and b are arranged in anupright pyramid configuration.

FIG. 6B illustrates a partial view of example touch screen 600 includingmetal traces 604 and 606 running in the border areas of the touch screenaccording to embodiments of the invention. Note that the border areas inFIG. 6B are enlarged for clarity. Each column a-h can include extendedyVcom line(s) 608 that allows the column to be connected to a metaltrace through a via (not shown in FIG. 6B). One side of each columnincludes staggered edges 614 and notches 616 designed to create separatesections in each column. Each row patch 1-6 can include extended yVcomline(s) 610 that allows the patch to be connected to a metal tracethrough a via (not shown in FIG. 6B). yVcom lines 610 can allow eachpatch in a particular row to be self-connected to each other. Becauseall metal traces 604 and 606 are formed on the same layer, they can allbe routed to the same flex circuit 602.

If touch screen 600 is operated as a mutual capacitance touch screen,either the columns a-h or the rows 1-6 can be driven with one or morestimulation signals, and fringing electric field lines can form betweenadjacent column areas and row patches. In FIG. 6B, it should beunderstood that although only electric field lines 612 between column aand row patch 1 (a-1) are shown for purposes of illustration, electricfield lines can be formed between other adjacent column and row patches(e.g. a-2, b-4, g-5, etc.) depending on what columns or rows are beingstimulated. Thus, it should be understood that each column-row patchpair (e.g. a-1, a-2, b-4, g-5, etc.) can represent a two-region touchpixel or sensor at which charge can be coupled onto the sense regionfrom the drive region. When a finger touches down over one of thesetouch pixels, some of the fringing electric field lines that extendbeyond the cover of the touch screen are blocked by the finger, reducingthe amount of charge coupled onto the sense region. This reduction inthe amount of coupled charge can be detected as part of determining aresultant “image” of touch. It should be noted that in mutualcapacitance touch screen designs as shown in FIG. 6B, no separatereference ground is needed, so no second layer on the back side of thesubstrate, or on a separate substrate, is needed.

Touch screen 600 can also be operated as a self-capacitance touchscreen. In such an embodiment, a reference ground plane can be formed onthe back side of the substrate, on the same side as the patches andcolumns but separated from the patches and columns by a dielectric, oron a separate substrate. In a self-capacitance touch screen, each touchpixel or sensor has a self-capacitance to the reference ground that canbe changed due to the presence of a finger. In self-capacitanceembodiments, the self-capacitance of columns a-h can be sensedindependently, and the self-capacitance of rows 1-6 can also be sensedindependently.

FIG. 6C illustrates an example connection of columns and row patches tothe metal traces in the border area of the touch screen according toembodiments of the invention. FIG. 6C represents “Detail A” as shown inFIG. 6B, and shows column “a” and row patches 4-6 connected to metaltraces 618 through yVcom lines 608 and 610. Because yVcom lines 608 and610 are separated from metal traces 618 by a dielectric material, vias620 formed in the dielectric material allow the yVcom lines to connectto the metal traces. The metal traces 618 can be formed in the samelayer as the yVcom lines. In this case, there would be no additionalprocess steps, and the touch traces can be routed in the same M1 and M2layers that are conventional in LCD's, also sometimes referred to as“gate metal” and “source/drain metal”. Also, the dielectric insulationlayer can be referred to as a “inner layer dielectric” or “ILD”.

As shown in FIG. 6C, column edges 614 and row patches 4-6 can bestaggered in the x-dimension because space should be made for the touchpixels containing yVcom lines 610 connecting row patches 4 and 5. (Itshould be understood that row patch 4 in the example of FIG. 6C isreally two patches stuck together.) To gain optimal touch sensitivity,it can be desirable to balance the area of the regions in touch pixelsa-6, a-5 and a-4. However, if column “a” was kept linear, row patch 6can be slimmer than row patch 5 or 6, and an imbalance would be createdbetween the regions of touch pixel a-6.

FIG. 7 illustrates a top view of an example column and adjacent rowpatches according to embodiments of the invention. It can be generallydesirable to make the mutual capacitance characteristics of touch pixelsa-4, a-5 and a-6 relatively constant to produce a relatively uniformz-direction touch sensitivity that stays within the range of touchsensing circuitry. Accordingly, the column areas a₄, a₅ and a₆ should beabout the same as row patch areas 4, 5 and 6. To accomplish this, columnsection a₄ and a₅, and row patch 4 and 5 can be shrunk in they-direction as compared to column section a6 and row patch 6 so that thearea of column segment a₄ matches the area of column segments a₅ and a₆.In other words, touch pixel a₄-4 will be wider but shorter than touchpixel a₆-6, which will be narrower but taller.

Because the touch pixels or sensors can be slightly skewed or misalignedin the x-direction, the x-coordinate of a maximized touch event on touchpixel a-6 (e.g. a finger placed down directly over touch pixel a-6) canbe slightly different from the x-coordinate of a maximized touch eventon touch pixel a-4, for example. Accordingly, in embodiments of theinvention this misalignment can be de-warped in a software algorithm tore-map the touch pixels and remove the distortion.

Although a typical touch panel grid dimension can have touch pixelsarranged on 5.0 mm centers, a more spread-out grid having about 6.0 mmcenters, for example, can be desirable to reduce the overall number ofelectrical connections in the touch screen. However, spreading out thesensor pattern can cause erroneous touch readings.

FIG. 8A is an example plot of an x-coordinate of a finger touch versusmutual capacitance seen at a touch pixel for a two adjacent touch pixelsa-5 and b-5 in a single row having wide spacings. In FIG. 8A, plot 800represents the mutual capacitance seen at touch pixel a-5 as the fingertouch moves continuously from left to right, and plot 802 represents themutual capacitance seen at touch pixel b-5 as the finger touch movescontinuously from left to right. As expected, a drop in the mutualcapacitance 804 is seen at touch pixel a-5 when the finger touch passesdirectly over touch pixel a-5, and a similar drop in the mutualcapacitance 806 is seen at touch pixel b-5 when the finger touch passesdirectly over touch pixel b-5. If line 808 represents a threshold fordetecting a touch event, FIG. 8A illustrates that even though the fingeris never lifted from the surface of the touch screen, it can erroneouslyappear at 810 that the finger has momentarily lifted off the surface.This location 810 can represent a point about halfway between the twospread-out touch pixels.

FIG. 8B is an example plot of an x-coordinate of a finger touch versusmutual capacitance seen at a touch pixel for a two adjacent touch pixelsa-5 and b-5 in a single row having wide spacings where spatialinterpolation has been provided according to embodiments of theinvention. As expected, a drop in the mutual capacitance 804 is seen attouch pixel a-5 when the finger touch passes directly over touch pixela-5, and a similar drop in the mutual capacitance 806 is seen at touchpixel b-5 when the finger touch passes directly over touch pixel b-5.Note, however, that the rise and fall in the mutual capacitance valueoccurs more gradually than in FIG. 8A. If line 808 represents athreshold for detecting a touch event, FIG. 8B illustrates that as thefinger moves from left to right over touch pixel a-5 and b-5, a touchevent is always detected at either touch pixel a-5 or b-5. In otherwords, this “blurring” of touch events is helpful to prevent theappearance of false no-touch readings.

In one embodiment of the invention, the thickness of the coverglass forthe touch screen can be increased to create part or all of the spatialblurring or filtering shown in FIG. 8B.

FIG. 8C illustrates a top view of an example column and adjacent rowpatch pattern useful for larger touch pixel spacings according toembodiments of the invention. FIG. 8C illustrates an example embodimentin which sawtooth region edges 812 are employed within a touch pixelelongated in the x-direction. The sawtooth region edges can allowfringing electric field lines 814 to be present over a larger area inthe x-direction so that a touch event can be detected by the same touchpixel over a larger distance in the x-direction. It should be understoodthat the sawtooth configuration of FIG. 8C is only an example, and thatother configurations such serpentine edges and the like can also beused. These configurations can further soften the touch patterns andcreate additional spatial filtering and interpolation between adjacenttouch pixels as shown in FIG. 8B.

FIG. 9A illustrates example touch screen 900 including sense (or drive)regions (C0-05) formed as columns 906 and rows of polygonal regions(bricks) 902, where each row of bricks forms a separate drive (or sense)region (R0-R7) according to embodiments of the invention. In the exampleof FIG. 9A, connecting yVcom lines 904 are routed along only one side ofthe bricks (a so-called “single escape” configuration). Although a touchscreen 900 having six columns and eight rows is shown, it should beunderstood that any number of columns and rows can be employed.

To connect bricks 902 in a particular row together, connecting yVcomlines 904, can be routed from the bricks along one side of the bricks ina single escape configuration to a particular bus line 910. Groundisolation regions 908, can be formed between connecting yVcom lines 904and adjacent columns 906 to reduce the capacitive coupling between theconnecting yVcom lines and the columns. Connections for each bus line910 and for columns 906 can be brought off touch screen 900 through flexcircuit 912.

FIG. 9B illustrates a close-up view of a portion of the example touchscreen 900 of FIG. 9A, showing how bricks 902 can be routed to bus lines910 using connecting yVcom lines 904 in a single escape configurationaccording to embodiments of the invention. In FIG. 9B, the longerconnections, more yVcom lines 904 (e.g. trace R7) can be used than theshorter connecting yVcom lines (e.g. trace R2) to equalize the overallresistivity of the traces and to minimize the overall capacitive loadsseen by the drive circuitry.

FIG. 9C illustrates a portion of example touch screen 900 of FIG. 9Aincluding bricks 902 associated with columns C0 and C1 and connectingyVcom lines 904 (illustrated symbolically as thin lines) connecting thebricks to bus lines 910 according to embodiments of the invention. Inthe example of FIG. 9B, which is drawn in a symbolic manner and not toscale for purposes of illustration only, bus line B0 is connected tobrick R0C0 (the closest brick to B0 adjacent to column C0) and R0C1 (theclosest brick to B0 adjacent to column C1). Bus line B1 is connected tobrick R1C0 (the next closest brick to B0 adjacent to column C0) and Rwho 1 (the next closest brick to B0 adjacent to column C1). The patternrepeats for the other bus lines such that bus line B7 is connected tobrick R7C0 (the farthest brick from B0 adjacent to column C0) and R7C1(the farthest brick from BO adjacent to column C1).

FIG. 10 illustrates a portion of example zig-zag double interpolatedtouch screen 1000 that can further reduce the stray capacitance betweenthe connecting yVcom lines and the sense regions according toembodiments of the invention. In the example of FIG. 10, polygonalregions 1002 representing the drive (or sense) regions are generallypentagonal in shape and staggered in orientation, with some of thepolygonal areas near the end of the panel being cut-off pentagons. Sense(or drive) regions 1004 are zig-zag shaped, with ground guards 1006between the sense (or drive) regions and pentagons 1002. All connectingyVcom lines 1008 are routed in channels 1010 between pentagons 1002. Inmutual capacitance embodiments, each touch pixel or sensor ischaracterized by electric field lines 1016 formed between a pentagon andan adjacent sense (or drive) region 1004. Because connecting yVcom lines1008 do not run alongside any sense (or drive) regions 1004, but insteadrun between pentagons 1002, the stray capacitance between connectingyVcom lines 1008 and sense (or drive) regions 1004 is minimized, andspatial cross-coupling is also minimized. Previously, the distancebetween connecting yVcom lines 1008 and sense (or drive) regions 1004was only the width of ground guard 1006, but in the embodiment of FIG.10, the distance is the width of the ground guard plus the width ofpentagon 1002 (which varies along the length of its shape).

As the example of FIG. 10 indicates, the pentagons for row R14 at an endof the touch screen can be truncated. Accordingly, the calculatedcentroids of touch 1012 for R14 can be offset in the y-direction fromtheir true position. In addition, the calculated centroids of touch forany two adjacent rows will be staggered (offset from each other) in thex-direction by an offset distance. However, this misalignment can bede-warped in a software algorithm to re-map the touch pixels and removethe distortion.

Although the foregoing embodiments of the invention have been primarilydescribed herein in terms of mutual capacitance touch screens, it shouldbe understood that embodiments of the invention are also applicable toself-capacitance touch screens as discussed above. In some embodiments,a touch screen can use both mutual and self-capacitance measurements ina time-multiplexing fashion to gather additional information and eachmeasurement type can compensate the weaknesses of the other.

Example displays including pixels with dual-function capacitiveelements, and the processes of manufacturing the displays, according toembodiments of the invention will now be described with reference toFIGS. 11-46. FIGS. 11-24 are directed to an example electricallycontrolled birefringence (ECB) LCD display using amorphous silicon(a-Si). FIGS. 25-34 are directed to an example IPS LCD display using lowtemperature polycrystalline silicon (LTPS). FIGS. 35-43 are directed toanother example IPS LCD display using LTPS. FIGS. 44-55 are directed toan example ECB LCD display using LTPS.

An example process of manufacturing an ECB LCD display according toembodiments of the invention will now be described with reference toFIGS. 11-18. The figures show various stages of processing of twopixels, a pixel 1101 and a pixel 1102, during the manufacture of the ECBLCD display. The resulting pixels 1101 and 1102 form electrical circuitsequivalent to pixels 101 and 102, respectively, of FIG. 1.

FIG. 11 shows the patterning of a first metal layer (M1) of pixels 1101and 1102. As shown in FIG. 11, the M1 layer for pixel 1102 includes agate 1155 a, a portion 1113 b of a gate line 1113, a lower electrode1157 b of a storage capacitor (not shown except for lower electrode 1157b), and a portion 1121 b of an xVcom 1121. Pixel 1101 includes a gate1105 a, a lower electrode 1107 b of a storage capacitor (not shownexcept for lower electrode 1107 b), a portion 1113 a of gate line 1113,and a portion 1121 a of xVcom 1121. Pixel 1101 also includes a portion1123 a of a yVcom 1123 (shown as dotted lines), which includes anadditional portion 1140. Portion 1123 a has a connection point 1141 anda connection point 1143. As shown in FIG. 11, a gate line 1113 and anxVcom 1121 run through both pixels 1101 and 1102 in an x-direction. Gateline 1113 connects to gates 1105 a and 1155 a, and xVcom 1121 connectslower electrode 1107 b and 1157 b. Portion 1123 a of yVcom 1123 connectsto xVcom 1121 in pixel 1101.

FIG. 12 shows a subsequent patterning step in the process ofmanufacturing pixels 1101 and 1102, in which island patterns ofamorphous silicon (a-Si) are formed. As can be seen FIG. 12, the islandpatterns for the pixels are similar, except that semiconductor portion1201 and 1203 of pixel 1102 are slightly different that semiconductorportions 1205 and 1207 of pixel 1101. For example, portion 1205 isslightly smaller than portion 1201. This is due, in part, to allow xVcom1121 to be connected in the vertical direction (y-direction) with otherxVcom lines through yVcom 1123, as is described in greater detail below.

FIG. 13 shows connections 1301 and 1302 formed in pixel 1101. Pixel 1102does not include such connections. The operation of connections 1301 and1302 is described in more detail below with reference to FIG. 14.

FIG. 14 shows patterning of a second metal layer (M2) of pixels 1101 and1102. As shown in FIG. 14, the M2 layer of pixel 1102 forms a portion1417 a of a green color data line, Gdata 1417 (shown as a dotted line inFIG. 14), a source 1455 b, a drain 1455 c, and an upper electrode 1457a. Similar to pixel 1102, the M2 layer of pixel 1101 forms a portion1415 a of a red color data line, Rdata 1415 (shown as a dotted line inFIG. 14), a source 1405 b, a drain 1405 c, and upper electrode 1407 a.The M2 layer of pixel 1101 also forms portions 1423 a and 1423 b ofyVcom 1123 (shown a dotted line in FIG. 14). Upper electrode 1407 a issmaller than upper electrode 1457 a, which allows portion 1423 a to beformed in the M2 layer of the pixel 1101. Portion 1423 a has aconnection point 1441, and portion 1423 b has a connection point 1443.

FIGS. 11, 13 and 14 together illustrate that pixel 1101 includes avertical common line (yVcom 1415) that allows connection of xVcom 1121with other xVcom lines in the vertical direction (y-direction). Inparticular, the figures show portion 1423 a is connected to portion 1123a through connection 1301 at connection points 1441 and 1141,respectively. Portion 1123 a is connected to 1423 b through connection1302 at points 1143 and 1443, respectively. Thus, the figures show acontinuous portion of yVcom 1123 is formed in pixel 1101 by theconnection of multiple structures of the pixel. As shown FIG. 11, yVcomportion 1123 a is connected to xVcom portion 1121 a. Consequently, thestructure of pixel 1101 shown in the figures allows connection in thevertical direction of multiple xVcom lines.

FIG. 15 shows planarization (PLN) contact layers 1501 and 1503 of pixels1101 and 1102, respectively. FIG. 16 shows reflector (REF) layers 1601and 1603 of pixels 1101 and 1102, respectively. FIG. 17 showspassivation (PASS) contacts 1701 and 1703 of pixels 1101 and 1102,respectively. FIG. 18 shows semi-transparent conductive material, suchas IPO, layers that form pixel electrodes 1801 and 1803 of pixels 1101and 1102, respectively.

FIG. 19 shows a plan view of completed pixels 1101 and 1102. FIGS. 20A-Billustrate side views of completed pixel 1101 take along the paths shownin the top views shown in the figures. FIGS. 20C-D illustrate side viewsof pixels 1102 and 1101 along the lines shown in FIG. 19.

FIG. 20A shows a side view of pixel 1101. The portion of the M1 layershown in FIG. 20A includes gate line portion 1113 b, gate 1155 a, lowerelectrode 1157 b, and xVcom portion 1121 b. The poly-Si layer shown inFIG. 20A includes poly-Si 1205 and poly-Si 1201. The M2 layer shown inFIG. 20A includes source 1455 b, drain 1465 c, and upper electrode 1457a. FIG. 20A also shows planarization layer 1503, reflector layer 1603,passivation contact 1703, and transparent conductor layer 1103.

FIG. 20B shows another side view of pixel 1101. For the sake of clarity,the planarization contact, reflector, passivation contact, andtransparent conductor layers are not shown in the figure. The M1 layershown in FIG. 20B includes gate line portion 1113 a, gate 1105 a, lowerelectrode 1107 b, and xVcom portion 1121 a. FIG. 20B also shows anadjacent pixel 2001, which has the same structure as pixel 1101. Thepoly-Si layer shown in FIG. 20B includes poly-Si portion 1211 andpoly-Si portion 1207. The M2 layer shown in FIG. 20B includes source1405 b, drain 1405 c, and upper electrode 1407 a.

FIG. 20C shows a side view of pixel 1102 along the line shown in FIG.19. The M1 layer shown in FIG. 20C includes gate line portion 1113 b,gate 1155 a, and xVcom portion 1121 b. FIG. 20C also shows a gateinsulator 2003 deposited on top of M1. Poly-Si portion 1203 and anadditional poly-Si portion are also shown in FIG. 20C.

FIG. 20D shows a side view of pixel 1101 along the line shown in FIG.19. The M1 layer shown in FIG. 20D includes gate line portion 1113 a,gate 1105 a, and yVcom portion 1123 a, which includes an intersectionwith xVcom portion 1121 a. Connections 1301 and 1302 contact connectionpoints 1141 and 1143, respectively, of yVcom portion 1123 a. FIG. 20Dalso shows a gate insulator layer 2005 and poly-Si portion 1209. The M2layer shown in FIG. 20D includes yVcom portion 1423 a, which connectswith connection 1301 at connection point 1441, and yVcom portion 1423 b,which connects with connection 1302 at connection point 1443. Thevertical common line, yVcom 1123 (shown in FIG. 20D as dashed lines)runs through pixel 1181 as yVcom portion 1423 a, connection 1301, yVcomportion 1123 a, connection 1302, and yVcom portion 1423 b. FIG. 20D alsoshows a portion of an adjacent pixel that includes structure identicalto pixel 1101. In particular, the adjacent pixel includes a yVcomportion that is connected, via a connection, to an xVcom portion. Thus,FIG. 20D illustrates that a xVcom portion 1121 a can be connected to anadjacent pixels xVcom portion with a yVcom line.

FIGS. 21 and 22 show a comparative analysis of the storage capacitanceof pixels 1101 and 1102. The total storage capacitance (Cstore) of pixel1102 is:

Cstore=C _(M1/M2) +C _(M1/ITO)  (1)

where: C_(M1/M2) is the capacitance of the overlapping M1 and M2 layers,such as upper electrode 1457 a and lower electrode 1157 b of pixel 1102,and

-   -   C_(M1/ITO) is the capacitance between overlapping areas of the        first metal layer and the transparent conductor layer.

For example, FIG. 21 shows the overlapping areas of the first and secondmetal layers that result in the capacitance C_(M1/M2). As shown in FIG.21, C_(M1/M2) of pixel 1102 results from an overlap of approximately 360square micrometers of the first and second metallic layers. Referringnow to FIG. 22, the highlighted portions of pixel 1102 show theoverlapping regions of the first metallic layer and the transparentconductor layer that result in C_(M1/ITO). As shown in FIG. 22, thetotal overlap is approximately 360 square micrometers.

In contrast, the total capacitance of pixel 1101 is:

Cstore=C _(M1/M2) +C _(M1/ITO) +C _(M2/ITO)  (2)

where: C_(M1/M2) and C_(M1/ITO) are defined as above, and

-   -   C_(M2/ITO) is the capacitance resulting from the overlap of the        second metallic layer and the transparent conductor layer.

The additional term in the storage capacitance equation for pixel 1101,C_(M2/ITO), results from the additional areas of the second metalliclayer in pixel 1101 that overlap with the transparent conductor layer.FIGS. 21 and 22 show the areas of overlapping metal in pixel 1101 thatresult in the terms of equation 2. FIG. 21 shows an overlapping regionof the first and second metallic layers in pixel 1101 that equalsapproximately 503 square micrometers. FIG. 22 shows overlapping regionsof the first metallic layer and the transparent conductor layer in pixel1101 that equals approximately 360 square micrometers. FIG. 22 alsoshows an overlapping region of the second metallic layer and thetransparent conductor layer that equals approximately 81 squaremicrometers. Thus, it is apparent from FIGS. 21 and 22 that, while thearea of overlap of the first and second metallic layers of pixel 1101 isless than the corresponding area of pixel 1102, pixel 1101 has an extraarea overlap that pixel 1102 does not. In particular, the overlap of thesecond metallic layer and the transparent conductor layer in pixel 1101contributes an additional 81 square micrometers, which in turncontributes an additional amount of capacitance to the storagecapacitance of pixel 1101.

FIG. 23 illustrates aperture ratio estimations for pixels 1101 and 1102.Pixel 1101 has an aperture ratio of 41.4%. Pixel 1102 has an apertureratio of 44.4%.

FIG. 24 illustrates an example modification according to embodiments ofthe invention. As a result of the modification, the aperture ratios ofthe different pixels in a system may be made more similar, which mayimprove the appearance of the display. Similar to pixel 1102, pixels2401 and 2405 do not include connection portions in the y-direction.Pixel 2403, on the other hand, does include a connection portion in they-direction, similar to pixel 1101.

FIGS. 25-34 are directed to an example IPS LCD display using lowtemperature polycrystalline silicon (LTPS). An example process ofmanufacturing an IPS LCD display using LTPS according to embodiments ofthe invention will now be described with reference to FIGS. 25-31. Thefigures show various stages of processing of two pixels, a pixel 2501and a pixel 2502, during the manufacture of the IPS LCD display usingLTPS. The resulting pixels 2501 and 2502 form electrical circuitsequivalent to pixels 101 and 102, respectively, of FIG. 1. Because thestages of processing shown in FIGS. 25-30 are the same for pixel 2501and pixel 2502, only one pixel is shown in each of these figures.However, it is understood that the stages of processing show in FIGS.25-30 apply to both pixel 2501 and pixel 2502.

FIG. 25 shows the patterning of a layer of poly-Si of pixels 2501 and2502. Semiconductor portions 2505, 2507, and 2509 form the active regionof a TFT, and serve as source, gate, and drain, respectively.

FIG. 26 shows a subsequent patterning step in the process ofmanufacturing pixels 2501 and 2502, in which a first metal layer (M1) ofpixels 2501 and 2502 is formed. As shown in FIG. 26, the M1 layer forthe pixels 2501/2502 includes a gate 2605 a, a portion 2613 a of a gateline 2613 (shown as dotted lines), and a portion 2621 a of xVcom 2621.Portion 2621 a includes a connection point 2623. Gate line 2613 andxVcom 2621 run through pixels that are adjacent in the x-direction.

FIG. 27 shows vias 2701, 2703, and 2705 formed in pixels 2501/2502 forconnections to portion 2505, portion 2509, and connection point 2623,respectively.

FIG. 28 shows patterning of a second metal layer (M2) of pixels2501/2502. As shown in FIG. 28, the M2 layer of the pixels forms aportion 2817 a of a color data line 2817 (shown as a dotted line in FIG.28), which could carry red, green, or blue color data, for example.Portion 2817 a includes a connection 2819 that connects to portion 2505through via 2701. The M2 layer also forms a connection 2821 with portion2509 through via 2703, and forms a connection 2823 to connection point2623 through via 2705.

FIG. 29 shows a first layer of transparent conductive material, such asITO, formed on pixels 2501/2502. The first transparent conductor layerincludes a pixel electrode 2901. FIG. 29 also shows a portion 2905 of apixel electrode of a pixel adjacent in the x-direction, and a portion2907 of a pixel electrode of a pixel adjacent in the y-direction. FIG.29 also shows a connection 2903, which forms a connection between acommon ITO layer described below and xVcom 2621 through connection point2623 and a connection 3001 shown in FIG. 30.

FIG. 31 shows a second layer of transparent conductor, such as ITO,formed on pixel 2501 and pixel 2502. The second layer on pixel 2502forms a common electrode 3151, which includes a connection point 3153that connects to xVcom 2621 through connections 3001 and 2903, andconnection point 2623. FIG. 31 also shows a portion 3155 of a commonelectrode of a pixel adjacent in the y-direction. Like pixel 2502, pixel2501 includes a common electrode 3101 formed of the second layer oftransparent conductor. Likewise, common electrode 3101 includes aconnection point 3103 that connects to xVcom 2621 through connections3001 and 2903, and connection point 2623. However, pixel 2501 alsoincludes a connection 3107 between common electrode 3101 and a commonelectrode 3105 of a pixel adjacent in the y-direction. In this way, thecommon electrodes of pixels can be connected in the y-direction to forma yVcom line 3109. Because common electrode 3101 is connected to xVcom2621 and xVcom 2621 is connected to common electrodes of other pixels inthe x-direction, the common electrodes of a region of pixels can beconnected together to form a touch sensing element. Similar to theprevious example embodiment, breaks in xVcom lines and yVcom lines cancreate separate regions of linked-together common electrodes that can beformed as an array of touch sensors.

FIG. 32 shows a plan view of completed pixels 2501 and 2502. FIG. 33illustrates a side view of pixel 2501 taken along the lines shown in thetop view shown in the figure.

FIG. 34 illustrates the storage capacitance of a pixel 2501 and a pixel2502.

FIGS. 35-43 are directed to another example IPS LCD display using LTPS.In the present example, a yVcom line is formed in an M2 layer (incomparison to the previous example IPS LCD display, in which a yVcomline is formed in a common ITO layer). An example process ofmanufacturing an IPS LCD display using LTPS with an M2 layer yVcom lineaccording to embodiments of the invention will now be described withreference to FIGS. 35-41. The figures show various stages of processingof two pixels, a pixel 3501 and a pixel 3502, during the manufacture ofthe example IPS LCD display. The resulting pixels 3501 and 3502 formelectrical circuits equivalent to pixels 101 and 102, respectively, ofFIG. 1.

FIG. 35 shows the patterning of a layer of poly-Si of pixels 3501 and3502. Semiconductor portions 3505, 3507, and 3509 form the active regionof a TFT of pixel 3501, and serve as source, gate, and drain,respectively. Likewise, semiconductor portions 3506, 3508, and 3510 arethe source, gate, and drain, respectively, of pixel 3502. FIG. 35 alsoshows that pixel 3501 has the width W′ (in the x-direction) that isslightly greater than the width W of pixel 3502.

FIG. 36 shows a subsequent patterning step in the process ofmanufacturing pixels 3501 and 3502, in which a first metal layer (M1) ofpixels 3501 and 3502 is formed. As shown in FIG. 36, the Ml layers ofpixels 3501 and 3502 include gates 3605 a and 3606 a, portions 3613 aand 3613 b of a gate line 3613 (shown as dotted lines), and portions3621 a and 3621 b of xVcom 3621. Portions 3621 a and 3622 a includeconnections points 3623 and 3624, respectively. Gate line 3613 and xVcom3621 run through pixels that are adjacent in the x-direction.

FIG. 37 shows vias 3701, 3703, and 3705 formed in pixels 3501 forconnections to portion 3505, portion 3509, and connection point 3623,respectively. Vias 3702, 3704, and 3706 formed in pixels 3502 forconnections to portion 3506, portion 3510, and connection point 3624,respectively.

FIG. 38 shows patterning of a second metal layer (M2) of pixels 3501 and3502. For pixel 3501, the M2 layer forms a portion 3817 a of a colordata line 3817 (shown as a dotted line in FIG. 38), which could carryred, green, or blue color data, for example. Portion 3817 a includes aconnection 3819 that connects to portion 3505 through via 3701. Pixel3501 also includes a portion 3830 a of a yVcom 3830 (shown as a dottedline), which includes a connection 3823 to connection point 3623 throughvia 3705. Thus, yVcom 3830 is connected to xVcom 3621. Pixel 3501 alsoincludes a connection 3821 with portion 3509 through via 3703.

Because yVcom 3830 is connected to xVcom 3621 and xVcom 3621 isconnected to common electrodes of other pixels in the x-direction, thecommon electrodes of a region of pixels can be connected together toform a touch sensing element. Similar to the previous exampleembodiment, breaks in xVcom lines and yVcom lines can create separateregions of linked-together common electrodes that can be formed as anarray of touch sensors.

For pixel 3502, the M2 layer forms a portion 3818 a of a color data line3818 (shown as a dotted line in FIG. 38), which could carry red, green,or blue color data, for example. Portion 3818 a includes a connection3820 that connects to portion 3506 through via 3702. Pixel 3501 alsoincludes a connection 3824 to connection point 3624 through via 3706,and a connection 3822 with portion 3510 through via 3704.

FIG. 39 shows a first layer of transparent conductive material, such asITO, formed on pixels 3501 and 3502. The first transparent conductorlayer includes pixel electrodes 3901 and 3905. FIG. 39 also showsconnections 3903 and 3907, which form connections between a common ITOlayer described below and xVcom 3621 through connection points 3623 and3624 and connections 4001 and 4002, respectively, shown in FIG. 40.

FIG. 41 shows a second layer of transparent conductor, such as ITO,formed on pixel 3501 and pixel 3502. The second layer on pixel 3502forms a common electrode 4107, which includes a connection point 4105that connects to xVcom 3621 through connections 4002 and 3907, andconnection point 3624 Like pixel 3502, pixel 3501 includes a commonelectrode 4101 formed of the second layer of transparent conductor.Likewise, common electrode 4101 includes a connection point 4103 thatconnects to xVcom 3621 through connections 4001 and 3903, and connectionpoint 3623.

FIG. 42 shows a plan view of completed pixels 3501 and 3502. FIG. 43illustrates a side view of pixel 3501 taken along the lines shown in thetop view shown in the figure.

FIGS. 44-55 are directed to an example ECB LCD display using LTPS. Likethe ECB LCD display using amorphous silicon (a-Si) (shown in FIGS.11-24), the process of manufacturing the ECB LCD display using LTPSincludes construction of vias and additional M2 lines to form yVcomlines that connect the storage capacitors of pixels in the y-direction.

An example process of manufacturing an ECB LCD display using LTPSaccording to embodiments of the invention will now be described withreference to FIGS. 44-50. FIG. 44 shows a semiconductor layer ofpoly-Si. FIG. 45 shows a first layer of metal (M1). FIG. 46 showsconnections including 4601 and 4602. FIG. 47 shows a second metal layer(M2). Connections 4601 and 4602 connect the M1 and M2 layers to form ayVcom line as shown in the figures. FIGS. 48-50 show a connection layer,a reflector layer, and an ITO layer, respectively. FIG. 51 shows acompleted pixel including a yVcom portion that allows connection in they-direction. FIG. 52 shows a side view of pixel 5101 along the lineshown in the top view shown in FIG. 52. FIG. 53 shows a calculation ofthe storage capacitance of pixel 5101. FIG. 54 shows an aperture ratioestimation of pixel 5101 and a pixel 5403 that does not include a yVcomline. FIG. 55 shows that some metal, such portions of the M1, M2, and/orITO layers can be shifted to help equalize the aperture ratios of thepixels.

FIG. 56 illustrates a portion of an example touch screen 5600 thatincludes a grounded separator region according to embodiments of theinvention. Similar to some embodiments described above, touch screen5600 includes regions for driving (5601 and 5602) and regions forsensing (5603 and 5604). The drive regions are connected to drive lines5611 and 5612, and the sense regions are connected to sense lines 5613and 5614. Touch screen also includes a grounded separator region 5605,which is a region of pixels having linked-together storage capacitors,as described above, that is grounded. Grounded separator region 5605 canhelp to electrically isolate touch pixel areas and may improve thedetection of touch by touch screen 5600. Grounded separator regions canbe, for example, evenly spaced throughout a touch screen.

FIG. 57 is a side view along the line A-A in FIG. 56, showing theportion of touch screen 5600, including a cover 5701, an adhesive 5702,a polarizer 5703, a high resistance (R) shield 5704, a color filterglass 5705, drive regions 5601 and 5602, sense regions 5603 and 5604,grounded separator region 5605, a TFT glass 5706, and a second polarizer5707. A high resistance shield, such as high R shield 5704, may be usedin touch screens using IPS LCD pixels, for example. A high R shield mayhelp block low frequency/DC voltages near the display from disturbingthe operation of the display. At the same time, a high R shield canallow high-frequency signals, such as those typically used forcapacitive touch sensing, to penetrate the shield. Therefore, a high Rshield may help shield the display while still allowing the display tosense touch events. High R shields may be made of, for example, a veryhigh resistance organic material, carbon nanotubes, etc. and may have aresistance in the range of 100 Mega-ohms per square to 10 Giga-ohms persquare.

FIG. 58 shows a side view of a portion of an example touch screen 5800according to embodiments of the invention. Touch screen 5800 includes acolor filter glass 5801, a pixel layer 5803 (including red (R), green(G), and blue (B) pixels, and black mask lines of a black mask, such asshown in FIG. 59). Touch screen 5800 also includes metal lines 5805under the black mask lines. Metal lines 5805 can provide low-resistancepaths, for example, between a region of pixels and bus lines in theborder of a touch screen. For example, in conventional LCD non-IPSdisplays, the common electrode, which is typically on the CF glass, isone sheet of ITO. Therefore, the resistance of this common electrode isvery low. For example, a conventional LCD may have a common electrode ofITO that has a resistance of approximately 100 ohms per square. However,in some embodiments above the common electrode is “broken up” intoregions that are connected to a shared common line through relativelythin pathways. The connection between a region of pixels and a sharedcommon electrode line can have a relatively high resistance,particularly if the region is further away from the boarder of the touchscreen, in which the shared common line may reside. Metal lines 5805 mayhelp lower the resistance of the path to such a region. Placing metallines 5805 under the black mask can reduce the metal lines' impact onpixel aperture ratio, for example.

FIG. 59 shows an example black mask layout according to embodiments ofthe invention. Black mask 5901 shields a yVcom line and a color dataline. Mask 5901 can help to reduce potential LCD artifacts betweendifferent regions. Mask 5902 shields a color data line. Mask 5901, whichcovers two lines, is wider than mask 5902.

As discussed in the above embodiments, at least some pixels includexVcom and/or yVcom lines. These lines are generally used to connect thecapacitors of various display pixels to form larger touch regions usedfor touch sensing (see, e.g., regions 207 and 205 of FIG. 2A and 257 and255 of FIG. 2B).

In the embodiments discussed above, the xVcom and yVcom lines are placedin the same layers as the gate and data lines. More specifically, xVcomlines are placed at the same layer as gate lines (see, e.g., FIG. 11,elements 1121 a and 1121 b), and yVcom lines span two layers the layerof the gate lines and the layer of the data lines (see, e.g., FIG. 11,element 1123 a and FIG. 12, elements 1423 a and 1423 b).

The xVcom and yVcom lines can be made out of a non-transparent conductor(such as non-transparent metal) in order to provide for lowerresistance. However, in the above discussed embodiments, the xVcom andyVcom lines can reduce the aperture of the display. While the abovediscussed embodiments attempt to minimize aperture reductions, somereductions as compared to a standard non-touch enabled display may stillbe necessary to accommodate the xVcom and yVcom lines.

Alternative embodiments discussed herein provide that xVcom and yVcomlines can be accommodated without any reductions of the aperture or,alternatively, with minimal reductions. This can be achieved by placingthe xVcom and yVcom lines on a different layer than the gate and datalines, and ensuring that the xVcom and yVcom lines overlap respectivegate and data lines. Thus, the xVcom and yVcom lines can be positionedabove or below respective gate and data lines and will not cause anyreductions in aperture that have not already been caused by the gate anddata lines. Thus, the addition of the touch functionality, or, in otherwords, the addition of the xVcom and yVcom lines, need not cause anyreductions in aperture.

Thus, in general, embodiments of the invention can feature common linesused for touch sensing that are positioned at a different layer thanvarious opaque display elements that are used for the displayfunctionality, and arranged so that the display elements substantiallyoverlap the common lines. The common lines can be attached to respectivestorage electrodes that are parts of storage capacitors used for variousdisplay pixels. Thus, the storage electrodes attached to the commonlines can serve a dual function—they can be used both for the displayand the touch sensing functionalities.

An example of one such embodiment is shown in FIG. 60. FIG. 60 showsthree exemplary layers of a display. First layer 6001 includes gate line6002. The second layer 6003 includes data line 6004. The first andsecond layers can be, for example the M1 and M2 layers. A third layer6005 includes an xVcom line 6006 that is positioned to overlap gate line6002 and a yVcom line 6007 that is positioned to overlap the data line6004. The xVcom and yVcom lines can be placed at the same layer andconnect in region 6008. Layers 6001, 6003 and 6005 need not be adjacent,but may be separated from each other by dielectric or other layers.Thus, the xVcom and yVcom lines need not connect to the gate and datalines they overlap.

The xVcom and yVcom lines need not be above the gate and data lines.They can alternatively be underneath the gate and data lines orpositioned at a layer between the gate and data lines. The xVcom andyVcom lines can be connected to pixel storage capacitors (or electrodesthereof). This can be achieved through vias, by positioning these linesat the same layer and adjacent to an electrode of the storage capacitoror by placing the xVcom and yVcom lines directly above or below anelectrode of the storage capacitor. Furthermore, the xVcom and yVcomlines can be positioned on different layers and may connect to eachother through vias.

Thus, by providing xVcom and yVcom lines that overlap respective gateand data lines, embodiments of the invention can ensure that theaddition of the xVcom and yVcom lines (or common lines) does not reducethe aperture of the display.

Some embodiments of the present invention may not require exact overlapbetween respective xVcom and yVcom lines and gate or data lines. Forexample, a xVcom or yVcom line can be narrower than, wider than, orslightly displaced from a respective gate or data line. Furthermore, acommon line need not only overlap a gate or data line, but may overlapany other nontransparent element required for the display functionality(such as, e.g., a pixel transistor) in order to ensure its addition doesnot cause a substantial reduction in aperture. For some embodiments, itis sufficient that the common line substantially overlaps anothernon-transparent element(s) in the display to ensure that the addition ofthe common line does not cause significant decrease of aperture. Forexample, the overlap can be such that only 70% of the common line isdirectly above or below a respective other non-transparent line orelement.

It should be noted that in this disclosure, the term overlap refers tothe ability of an opaque element (such as a gate line, data line, oranother element) to “cover” the common lines. Thus, a substantialoverlap may indicate that certain significant percentage of the commonlines is covered (such as, e.g., 70%) by other opaque elements, and acomplete overlap (which includes a substantial overlap) takes place whenthe entire common lines are covered. For the term overlap, as definedherein, it need not be significant whether the common lines arepositioned over the other opaque element(s) or under them. Furthermore,only the ability of other elements to cover the common lines may beconsidered significant. If the common lines fail to cover large portionsof other elements, this need not be considered relevant for determiningoverlap.

As noted above, some embodiments of the invention relate to FFS TFTdisplays. As known in the art, FFS TFT displays can be provided in twopossible configurations as relating to the relative placement of theircommon and pixel electrodes. These are referred to as the “common ontop” configuration in which the common electrode is placed on top of thepixel electrode and the “pixel on top” configuration in which the pixelelectrode is placed on top of the common electrode. FIGS. 61A and 61Bshow these configurations in more detail. FIG. 61A shows a pixelelectrode on top configuration and FIG. 61B shows a common electrode ontop configuration. It should be noted that to improve clarity, FIGS. 61Aand 61B do not show other known elements of the display such as gate anddata lines, transistors, etc.

In FIG. 61A, the common electrode is electrode 6100. Multiple pixelelectrodes 6101-6104 can be positioned above it. Each pixel electrodecan include two or more “fingers” or extensions. Thus, for example,fingers 6105, 6106 and 6107 can be part of pixel electrode 6102. Thefingers of a single pixel electrode can be interconnected to form asingle electrode (this connection is not shown in the cross section ofFIG. 61A). When a pixel electrode is at a different voltage than thecommon electrode 6100, electrical fields appear between the pixelelectrode and the common electrode. Some of these extend above the pixelelectrode (see, e.g., fields 6108 of electrode 6101) and can controlliquid crystals above the pixel electrode in order to change the visiblestate of a pixel associated with the pixel electrode. The voltage ofeach pixel electrode can be individually changed to control the color(or brightness) of a particular pixel, while the single common electrode6100 can be maintained at a single voltage for all pixels (although somedisplays can use a plurality of different common electrodes fordifferent rows).

FIG. 61B shows a common electrode on top configuration. In this case,pixel electrodes 6111, 6112, 6113 and 6114 can be positioned along thebottom of the display. As shown, the pixel electrodes need not beseparated into fingers. The common electrode 6110 can be positioned overthe pixel electrodes and form sets of fingers over each pixel electrode.All the fingers of the common electrode can be connected, thus forming asingle common electrode 6110. The three fingers 6110 above pixelelectrode 6111 can be connected to fingers 6110 above pixel electrodes6112, 6113 and 6114. Again this connection is not shown in the crosssection of FIG. 61B. However, as noted above, some embodiments mayfeature different common electrodes on different lines. Thus, the commonelectrode on the top embodiment is not a single solid plate but can becut into stripes in order to allow for the forming of fingers.

In FFS TFT embodiments, the common lines (i.e., xVcom and yVcom, orgenerally VCOM) can be made adjacent to the common electrode in order toensure that they are conductively connected. FIGS. 62A-D show someexemplary connections.

In FIG. 62A the common line 6201 is immediately above the commonelectrode 6200. In FIG. 62B, the common line 6201 is immediately belowthe common electrode 6200. In FIG. 62C, the common line 6201 is abovethe common electrode 6200, but not immediately above it. Instead, theremay be some space between the common electrode and the common bus line.This space may be occupied by another layer, such as a dielectric.Connections 6202 can be used to connect the common electrode to thecommon line instead. In FIG. 62D, the common line is placed at the samelayer as the common electrode.

It should be noted that the configurations shown in FIGS. 62A-62D arenot the only configurations for embodiments of this invention. Forexample, the common line can be placed below the common electrode butnot immediately below it and may utilize connections to connect to thecommon electrode. Also, FIGS. 62A-D show a solid common electrode, whichwould indicate a common electrode on the bottom configuration. Those ofskill in the art would recognize the connections of FIGS. 62A-D can beeasily applied to a common electrode on top configuration. Theconnections of FIGS. 62A-D can also be used to connect common lines tostorage electrodes in non-FFS embodiments. In the interest of clarity,FIGS. 62A-62D do not show all components of the display.

FIG. 63 is a diagram showing FFS TFT LCD embodiments of the presentinvention in various stages of manufacturing. Diagrams 6301-6309represent different stages of the manufacturing of a substrate assemblythat result from placing different elements on a substrate (which maybe, e.g., a glass substrate). More specifically, stages 6301-6309 areprogressive stages of manufacturing of a display pixel on a substrate inwhich various features are sequentially placed on the substrate and thusadded to the substrate assembly. Thus, every stage can include all theelements of its predecessor stage.

Elements formed when manufacturing the substrate assembly are consideredto be formed on the substrate and part of the substrate assembly even ifthey are not formed directly on the substrate but are formed on top ofother elements that are formed on the substrate. There are, however,other layers that are part of the display but are not formed on thesubstrate or on another element that is formed on the substrate. Theseare instead separately produced and later combined with the substrate.These layers can include filters, polarizers, liquid crystals, othersubstrates, etc. They may not considered to be part of the substrateassembly.

At stage 6301, poly-silicon 6319 is placed on the substrate. Stages6302-6304 are not shown, but they are conventional. In stage 6302 afirst metal layer is placed. This can form, for example, gate line 6310.In stage 6303, a first dielectric/connection layer is placed. In stage6304, a second metal layer is placed. The second metal layer can form,for example, data line 6311. In stage 6305, a seconddielectric/connection layer is placed. At this point a transistor 6317is formed. The transistor has a source connected to the data line 6311,a gate connected to the gate line 6310 and a drain 6318 that will beconnected to the pixel electrode (see below).

In stage 6306, a common ITO layer is placed. The common ITO layer canform common electrode 6312. In FIG. 63, the common electrode 6312 isplaced (e.g., deposited or otherwise fabricated) in the common electrodeat the bottom configuration.

In stage 6307 another metal feature can be placed. This is referred tothe common metal stage and can involve placing the common (VCOM) lines6321 and 6322. More specifically, 6321 can be the xVcom line and 6322can be the yVcom line. The xVcom line 6321 can be placed directly abovethe gate line 6310 and the yVcom line 6322 can be placed directly abovethe data line 6311 in order to ensure that placement of the common linesdoes not decrease the aperture of the cell. As noted above, in someembodiments, the common lines need not line up with the gate and datalines exactly. For example, the common lines may be slightly thicker orslightly displaced from the respective gate or data line and thus maycause a slight decrease in aperture.

The common lines can be placed at the same layer and can thus beconductively connected at their junctures (such as juncture 6323).Furthermore, the common lines 6321 and 6322 can be placed on the samelayer as the common electrode 6312 and can share sides with it (see,e.g., FIG. 62D). It should be noted that the common lines can beinsulated from the gate and data lines 6310 and 6311 by, for example,the dielectric applied at stage 6305. At stage 6309, the pixel electrode6315 is placed. Since this embodiment is of the pixel electrode on toptype, the pixel electrode is placed above the common electrode and has acomb like shape (see, e.g., FIG. 61A). As with the common electrode, thepixel electrode can be formed from ITO. The pixel electrode 6315 can beconnected to the drain 6318 of transistor 6317 by way of connection6320.

It can be seen that the aperture ratio 6316 is not significantlydecreased from what it would have been had the common lines 6321 and6322 been absent. In other words, the placement of common lines does notoverlap any areas that could have otherwise been used for the displayfunctionality. To the contrary, the common lines overlap areas that arealready opaque due to other needed elements (e.g., gate line 6310 anddata line 6311).

FIG. 64 shows a larger portion of the LCD of FIG. 63. There, multiplepixels can be seen. The multiple pixels can be connected throughmultiple xVcom lines 6321 and yVcom lines 6322. FIG. 64 also showsbreaks 6400 of the xVcom and yVcom lines. These breaks can be used toseparate/define different touch regions (see, e.g., FIGS. 2A and 2B andrelated discussion above). The breaks in the xVcom and yVcom lines canbe accompanied by corresponding breaks in the underlying commonelectrode in order to ensure that the different touch regions are notelectrically connected through the common electrode. Thus each commonelectrode can form its own touch region.

FIG. 65 is a diagram of various manufacturing stages of an exemplarydisplay according to one embodiment of the invention. In contrast toFIG. 63, FIG. 65 shows a common electrode on top configuration. Stages6501-6505 are similar to stages 6301-6305, respectively. As with theembodiment of FIG. 63, a transistor 6317 is formed at stage 6504. Thetransistor can be the same as transistor 6317 of FIG. 63. At stage 6506,the pixel electrode 6515 is initially deposited. The pixel electrode isconnected to the drain 6318 of transistor 6317. Stage 6507 is aconnection and dielectric layer. At stage 6508, the common electrode6512 is placed. In this embodiment, the common electrode is above thepixel electrode. Thus, the common electrode can be comb-like, as shown(see also FIG. 61B).

At stage 6509, the common lines 6321 and 6322 are placed. The commonlines may be placed at the same layer as the common electrode 6512 andmay share a side with it to provide an electrical connection (see, e.g.,FIG. 62D). Similarly to the embodiment of FIG. 63 the yVcom line 6322overlaps data line 6311. However, in this example, the xVcom line 6321does not overlap gate line 6310. This is not required—the xVcom line6321 can overlap the gate line 6310 in other common electrode on topembodiments. However, in this embodiment, the xVcom line 6321 ispositioned a little forward in relation to the gate line 6310.Nevertheless, the xVcom line does not substantially (or at all) reducethe aperture of the device, because it is placed directly above otheropaque features of the device, such as the drain 6318 of transistor 6317and the poly-silicon 6319. Again, the xVcom and yVcom lines can bepositioned on the same layer and can be conductively connected at theirintersections.

Other embodiments may feature configurations different from those shownin FIGS. 63 and 65. For example, the common lines 6321 and 6322 can bepositioned below the gate and data lines.

FIG. 66 shows a larger portion of the LCD of FIG. 65. Similarly to FIG.64, FIG. 66 shows various breaks in the xVcom and yVcom lines 6321 and6322 which are used to form different touch regions (see, e.g., FIGS. 2Aand 2B and accompanying discussion). Again the breaks of the xVcom andyVcom lines can be accompanied by corresponding breaks in the commonelectrode to ensure insulation between neighboring touch regions.

The embodiments of FIGS. 61-66 refer to FFS TFT LCDs. However, theteachings discussed therein can be used for other types of LCDs. Thus,other types of LCDs can feature xVcom and yVcom lines that overlapexisting opaque elements of the display that are already used to performdisplay functionality (such as, e.g., gate and data lines) in order toensure that the xVcom and yVcom lines do not cause any reductions to theaperture ratio. Non-FFS embodiments need not include a common electrode.However, they can include pixel storage capacitors. Thus, in theseembodiments the xVcom and/or yVcom lines can be attached to an electrodeof the pixel storage capacitor of each pixel. In some embodiments, thexVcom and yVcom lines can be positioned at the same TFT substrateassembly as the transistors and gate and data lines of each electrode.In other embodiments, the xVcom and yVcom lines can be positioned in acolor filter layer above the TFT layer, as discussed above (see, e.g.,FIG. 2B). In the latter embodiments, the xVcom and yVcom lines cannevertheless be lined up to overlap respective gate and data lines ofthe TFT layer.

FIG. 67 shows an example IPS-based touch-sensing display in which thepixel regions serve multiple functions. For example, a pixel region canoperate as a drive region at one time and operate as a sensing region atanother time. FIG. 67 shows two types of pixel regions, pixel regiontype A and pixel region type B. During a first time period the A typepixel regions, i.e., touch columns, can be driven with a stimuluswaveform while the capacitance at each of the B type pixel regions,i.e., touch rows, can be sensed. During a next time period, the B typepixel regions, i.e., touch rows, can be driven with a stimulus waveformwhile the capacitance at each of the A type pixel regions, i.e., touchcolumns, can be sensed. This process can then repeat. The twotouch-sense periods can be about 2 ms. The stimulus waveform can take avariety of forms. In some embodiments it may be a sine wave of about 5Vpeak-to-peak with zero DC offset. Other time periods and waveforms mayalso be used.

FIG. 68 illustrates an example computing system 6800 that can includeone or more of the embodiments of the invention described above.Computing system 6800 can include one or more panel processors 6802 andperipherals 6804, and panel subsystem 6806. Peripherals 6804 caninclude, but are not limited to, random access memory (RAM) or othertypes of memory or storage, watchdog timers and the like. Panelsubsystem 6806 can include, but is not limited to, one or more sensechannels 6808, channel scan logic 6810 and driver logic 6814. Channelscan logic 6810 can access RAM 6812, autonomously read data from thesense channels and provide control for the sense channels. In addition,channel scan logic 6810 can control driver logic 6814 to generatestimulation signals 6816 at various frequencies and phases that can beselectively applied to drive lines of touch screen 6824. In someembodiments, panel subsystem 6806, panel processor 6802 and peripherals6804 can be integrated into a single application specific integratedcircuit (ASIC).

Touch screen 6824 can be a combination of a display and touch screen asdiscussed above. Touch screen 6824 can include a capacitive sensingmedium having a plurality of drive regions and a plurality of senseregions according to embodiments of the invention. Each intersection ofdrive and sense regions can represent a capacitive sensing node and canbe viewed as touch picture element (touch pixel) 6826, which can beparticularly useful when touch screen 6824 is viewed as capturing an“image” of touch. (In other words, after panel subsystem 6806 hasdetermined whether a touch event has been detected at each touch sensorin the touch screen, the pattern of touch sensors in the multi-touchpanel at which a touch event occurred can be viewed as an “image” oftouch (e.g. a pattern of fingers touching the panel).) Each sense regionof touch screen 6824 can drive sense channel 6808 (also referred toherein as an event detection and demodulation circuit) in panelsubsystem 6806.

Computing system 6800 can also include host processor 6828 for receivingoutputs from panel processor 6802 and performing actions based on theoutputs that can include, but are not limited to, moving an object suchas a cursor or pointer, scrolling or panning, adjusting controlsettings, opening a file or document, viewing a menu, making aselection, executing instructions, operating a peripheral deviceconnected to the host device, answering a telephone call, placing atelephone call, terminating a telephone call, changing the volume oraudio settings, storing information related to telephone communicationssuch as addresses, frequently dialed numbers, received calls, missedcalls, logging onto a computer or a computer network, permittingauthorized individuals access to restricted areas of the computer orcomputer network, loading a user profile associated with a user'spreferred arrangement of the computer desktop, permitting access to webcontent, launching a particular program, encrypting or decoding amessage, and/or the like. Host processor 6828 can also performadditional functions that may not be related to panel processing, andcan be connected to program storage 6832. The processor can also beconnected to the touch screen/display combination 6824 in order tocontrol the display functionality. This connection can be distinct andin addition to the connection between the host processor 6828 and thetouch screen display combination 6824 through the panel processor 6802,said latter connection being used to control the touch functionality ofthe touch screen display combination 6824.

Note that one or more of the functions described above can be performedby firmware stored in memory (e.g. one of the peripherals 6804 in FIG.68) and executed by panel processor 6802, or stored in program storage6832 and executed by host processor 6828. The firmware can also bestored and/or transported within any computer-readable medium for use byor in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “computer-readable medium” can be anymedium that can contain or store the program for use by or in connectionwith the instruction execution system, apparatus, or device. Thecomputer readable medium can include, but is not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus or device, a portable computer diskette(magnetic), a random access memory (RAM) (magnetic), a read-only memory(ROM) (magnetic), an erasable programmable read-only memory (EPROM)(magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R,or DVD-RW, or flash memory such as compact flash cards, secured digitalcards, USB memory devices, memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport readable medium can include, but is not limitedto, an electronic, magnetic, optical, electromagnetic or infrared wiredor wireless propagation medium.

FIG. 69A illustrates an example mobile telephone 6936 that can include atouch screen 6924, the touch screen including pixels with dual-functioncapacitive elements according to embodiments of the invention.

FIG. 69B illustrates an example digital media player 6940 that caninclude touch screen 6924, the touch screen including pixels withdual-function capacitive elements according to embodiments of theinvention.

FIG. 69C illustrates an example personal computer 6944 that can includea trackpad 6925 that is a touch screen, including pixels withdual-function capacitive elements. Alternatively or in addition, thepersonal computer 6944 can include a touch screen 6924 that is used asthe main display of the personal computer. The touch screen 6924 canalso include pixels with dual function capacitive elements according toembodiments of the invention.

Although embodiments of this invention have been fully described withreference to the accompanying drawings, it is to be noted that variouschanges and modifications will become apparent to those skilled in theart. Such changes and modifications are to be understood as beingincluded within the scope of embodiments of this invention as defined bythe appended claims.

What is claimed is:
 1. A touch screen having a touch sensor panel and adisplay device, the touch screen configured to perform both a displayand a touch sensing functionality comprising: a plurality of pixels,each pixel including a storage capacitor comprising a first electrodeand a second electrode, the plurality of pixels forming drive regionsand sense regions; one or more opaque display elements used to performthe display functionality of the touch screen; and a plurality of commonlines made from a non-transparent conductor, connected to the firstelectrode of one or more of the plurality of pixels and positioned at adifferent layer in the touch screen than the opaque display elementssuch that the opaque display elements and the common lines substantiallyoverlap one another ; wherein the opaque display elements contribute toan aperture ratio of the display device and the plurality of commonlines substantially maintain the aperture ratio of the display device;and wherein the first electrodes connected to the common lines are usedin the touch sensing functionality for drive signals in the driveregions and sense signals in the sense regions, the sense signalsgenerated by capacitive coupling between the drive and sense regions;and wherein the first electrodes connected to the common lines are usedin the display functionality for display data signals.
 2. The touchscreen of claim 1, wherein the common lines are connected to touchcircuitry during the touch sensing functionality.
 3. The touch screen ofclaim 1, wherein the common lines include a first plurality of parallelcommon lines and a second plurality of parallel common lines, the firstand second pluralities being positioned perpendicular to one another atthe same layer to form a lattice structure.
 4. The touch screen of claim3, wherein the opaque display elements include a plurality of parallelgate lines and a plurality of parallel data lines, the gate and datalines being positioned perpendicular to each other to form a latticestructure, wherein: the first plurality of common lines aresubstantially overlapped by the gate lines; and the second plurality ofcommon lines are substantially overlapped by the data lines.
 5. Thetouch screen of claim 1, wherein the opaque display elements include atleast one of display gate and data lines.
 6. The touch screen of claim1, wherein the opaque display elements include pixel transistors.
 7. Thetouch screen of claim 1, wherein the plurality of common lines areconfigured to connect the pixels in a plurality of sets of pixels, eachset of pixels having all first electrodes connected to each other by thecommon lines, and wherein the common lines are interrupted at theboundaries between different adjacent sets of pixels.
 8. The touchscreen of claim 7, wherein each set of pixels comprises a touch region,and wherein selected pairs of touch regions form touch pixels comprisingat least one drive region and at least one sense region, the touchpixels capable of indicating a touch event thereon by changes in acapacitance between the pair of touch regions.
 9. The touch screen ofclaim 7, wherein each set of pixels covers a contiguous region of thetouch screen.
 10. A mobile media player including the touch screen ofclaim
 1. 11. A mobile telephone including the touch screen of claim 1.12. A personal computer including the touch screen of claim
 1. 13. Adigital media player including a touch screen having a touch sensorpanel and a display device, the touch screen configured to perform botha display and a touch sensing functionality, comprising: a plurality ofpixels, each pixel including a storage capacitor comprising a firstelectrode and a second electrode, the plurality of pixels forming driveregions and sense regions; one or more opaque display elements used toperform the display functionality of the touch screen; and a pluralityof common lines made from a non-transparent conductor, connected to thefirst electrode of one or more of the plurality of pixels and positionedat a different layer in the touch screen than the opaque displayelements such that the opaque display elements and the common linessubstantially overlap one another the common lines; wherein the opaquedisplay elements contribute to an aperture ratio of the display deviceand the plurality of common lines substantially maintain the apertureratio of the display device; and wherein the first electrodes connectedto the common lines are used in the touch sensing functionality fordrive signals in the drive regions and sense signals in the senseregions, the sense signals generated by capacitive coupling between thedrive and sense regions; and wherein the first electrodes connected tothe common lines are used in the display functionality for display datasignals.
 14. A mobile telephone including a touch screen having a touchsensor panel and a display device, the touch screen configured toperform both a display and a touch sensing functionality, comprising: aplurality of pixels, each pixel including a storage capacitor comprisinga first electrode and a second electrode; one or more opaque displayelements used to perform the display functionality of the touch screen;and a plurality of common lines made from a non-transparent conductor,connected to the first electrode of one or more of the plurality ofpixels and positioned at a different layer in the touch screen than theopaque display elements such that the opaque display elements and thecommon lines substantially overlap one another; wherein the opaquedisplay elements contribute to an aperture ratio of the display deviceand the plurality of common lines substantially maintain the apertureratio of the display device; and wherein the first electrodes connectedto the common lines are used in the touch sensing functionality fordrive signals in the drive regions and sense signals in the senseregions, the sense signals generated by capacitive coupling between thedrive and sense regions; and wherein the first electrodes connected tothe common lines are used in the display functionality for display datasignals.
 15. A touch screen having a touch sensor panel and a displaydevice, the touch screen configured to perform both a display and atouch sensing functionality, comprising: a plurality of pixels includinga plurality of sets of pixels, each set of pixels comprising two or morepixels; a plurality of common electrodes, each common electrode servingas a storage capacitor electrode for a respective set of pixels; one ormore opaque display elements used to perform the display functionalityof the touch screen; and a plurality of common lines made from anon-transparent conductor, connected to the plurality of commonelectrodes and positioned at a different layer in the touch screen thanthe opaque display elements such that the opaque display elements andthe common lines substantially overlap one another; wherein the opaquedisplay elements contribute to an aperture ratio of the display deviceand the plurality of common lines substantially maintain the apertureratio of the display device; and wherein the first electrodes connectedto the common lines are used in the touch sensing functionality fordrive signals in the drive regions and sense signals in the senseregions, the sense signals generated by capacitive coupling between thedrive and sense regions; and wherein the first electrodes connected tothe common lines are used in the display functionality for display datasignals.
 16. The touch screen of claim 15, wherein the common lines arepositioned at the same or adjacent layer to the plurality of commonelectrodes.
 17. The touch screen of claim 15, wherein each commonelectrode is connected to a respective set of plurality of common linesfrom the plurality of common lines, and wherein the common lines areinterrupted at the boundaries between different adjacent commonelectrodes.
 18. The touch screen of claim 17, wherein the common linesinclude breaks at the borders of the common electrodes.
 19. The touchscreen of claim 17, wherein each common electrode comprises a touchregion and selected pairs of touch regions form touch pixels comprisingat least one drive region and at least one sense region, the touchpixels capable of indicating a touch event thereon by changes in acapacitance between said pair of touch regions.
 20. The touch screen ofclaim 15, wherein the touch screen comprises an FFS TFT LCD.
 21. Amethod for manufacturing a touch screen having a touch sensor panel anda display device, the touch screen configured to perform both a displayand a touch sensing functionality comprising: forming a plurality ofpixels, each pixel including a storage capacitor comprising a firstelectrode and a second electrode; forming drive and sense regions fromthe plurality of pixels; forming one or more opaque display elementsused to perform the display functionality of the touch screen; forming aplurality of common lines from a non-transparent conductor, the commonlines being positioned at a different layer in the touch screen than theopaque display elements such that the opaque display elements and thecommon lines substantially overlap one another; and connectingrespective ones of the plurality of common lines to one or more of thefirst electrodes of the plurality of pixels; wherein the opaque displayelements contribute to an aperture ratio of the display device and theplurality of common lines substantially maintain the aperture ratio ofthe display device; and wherein the first electrodes connected to thecommon lines are used in the touch sensing functionality for drivesignals in the drive regions and sense signals in the sense regions, thesense signals generated by capacitive coupling between the drive andsense regions; and wherein the first electrodes connected to the commonlines are used in the display functionality for display data signals.22. The method of claim 21, wherein the common lines are connected totouch circuitry during the touch sensing functionality.
 23. The methodof claim 21, wherein the forming of the common lines comprises: forminga first plurality of parallel common lines ; and forming a secondplurality of parallel common lines, the first and second pluralitiesbeing positioned perpendicular to one another at the same layer to forma lattice structure.
 24. The method of claim 23, wherein the forming ofthe opaque display elements comprises: forming a plurality of parallelgate lines; forming a plurality of parallel data lines; and positioningthe gate and data lines perpendicular to each other to form a latticestructure, wherein the first plurality of common lines are respectivelysubstantially overlapped by respective gate lines, and the secondplurality of common lines are respectively substantially overlapped byrespective data lines.
 25. The method of claim 21, wherein forming theopaque display elements comprises forming display gate and data lines.26. The method of claim 21, wherein the forming of the opaque displayelements comprises forming of pixel transistors.
 27. The method of claim21, wherein the plurality of common lines are configured to connect thepixels in a plurality of sets of pixels, each set of pixels having allfirst electrodes connected to each other by the common lines and whereinthe common lines are interrupted at the boundaries between differentadjacent sets of pixels.
 28. The method of claim 27, wherein each setsof pixels comprises a touch region, and selected pairs of touch regionsform touch pixels comprising at least one drive region and at least onesense region, the touch pixels capable of indicating a touch eventthereon by changes in a capacitance between said pair of touch regions.29. The method of claim 27, wherein each set of pixels covers acontiguous region of the touch screen.
 30. A method for manufacturing atouch screen having a touch sensor panel and a display device, the touchscreen configured to perform both a display and a touch sensingfunctionality including: forming a plurality of pixels including aplurality of sets of pixels, each set of pixels comprising two or morepixels; forming drive and sense regions from the plurality of sets ofpixels; forming a plurality of common electrodes, each common electrodeserving as a storage capacitor electrode for a respective set of pixels;forming one or more opaque display elements used to perform the displayfunctionality of the touch screen; forming a plurality of common linesfrom a non-transparent conductor and positioned at a different layer inthe touch screen than the opaque display elements such that the opaquedisplay elements and the common lines substantially overlap one another;and connecting the plurality of common lines to the plurality of commonelectrodes, wherein the opaque display elements contribute to anaperture ratio of the display device and the plurality of common linessubstantially maintain the aperture ratio of the display device; andwherein the common electrodes connected to the common lines are used inthe touch sensing functionality for drive signals in the drive regionsand sense signals in the sense regions, the sense signals generated bycapacitive coupling between the drive and sense regions; and wherein thecommon electrodes connected to the common lines are used in the displayfunctionality for display data signals.
 31. The method of claim 30,wherein forming the common lines comprises positioning the common linesat the same or adjacent layer to the plurality of common electrodes. 32.The method of claim 30, wherein each common electrode is connected to aset of plurality of common lines from the plurality of common lines andwherein the common lines are interrupted at the boundaries betweendifferent adjacent common electrodes.
 33. The method of claim 32,wherein forming the common lines includes ensuring there are breaks ofthe common lines at the borders of the common electrodes.
 34. The touchscreen of claim 32, wherein each common electrode comprises a touchregion, and selected pairs of touch regions form touch pixels comprisingat least one drive region and at least one sense region, the touchpixels capable of indicating a touch event thereon by changes in acapacitance between said pair of touch regions.
 35. The method of claim30, wherein the touch screen comprises an FFS TFT LCD.
 36. A personalcomputer including a touch screen having a touch sensor panel and adisplay device, the touch screen configured to perform both a displayand a touch sensing functionality, comprising: a plurality of pixels,each pixel including a storage capacitor comprising a first electrodeand a second electrode, the plurality of pixels forming drive regionsand sense regions; one or more opaque display elements used to performthe display functionality of the touch screen; and a plurality of commonlines made from a non-transparent conductor, connected to the firstelectrode of one or more of the plurality of pixels and positioned at adifferent layer in the touch screen than the opaque display elementssuch that the opaque display elements and the common lines substantiallyoverlap one another; wherein the opaque display elements contribute toan aperture ratio of the display device and the plurality of commonlines substantially maintain the aperture ratio of the display device;and wherein the first electrodes connected to the common lines are usedin the touch sensing functionality for drive signals in the driveregions and sense signals in the sense regions, the sense signalsgenerated by capacitive coupling between the drive and sense regions;and wherein the first electrodes connected to the common lines are usedin the display functionality for display data signals.